Chapter X: BIOGRAPHY.--Gaston Plante, the Scientist.--With portrait (2)

The very peculiar method of driving and steering, which seems so puzzling to the novice, especially if he is a good rider of other machines--for in that case he is far worse off than one who has never ridden anything--give the rider, when he is familiar with them, a control over the machine which is still surprising to me. In the first place, the machine will run along straight, backward or forward, so long as the handles are let alone. This automatic straight running is a luxury, for until a deviation has to be made, the steering handles need not be touched, and the rider may, if sufficiently confident, travel with his arms folded or his hands in his pockets. The rigid connection between the cranks and the wheels does away with all the backlash, which is so unpleasant with chain or toothed wheel gearing. There is no differential gear or clutch, but the machine possesses the advantage of the clutch over the differential gear when meeting with unequal resistance on a straight course, for each wheel must travel at the same speed; but, in turning a corner, instead of driving the inner wheel only, which is done by the clutch or both wheels equally, which is the case with differential gear, each wheel is driven, but the outer one more than the inner. At high speeds, the steering of the Otto has this advantage, that whereas, with a given action on a tricyle, the same deviation will be effected in the same _space_ at high as at low speeds, the same action on the Otto will, at high speeds, produce the same deviation in the same _time_ as it does at low speeds; and so instead of becoming more sensitive at high speeds, as is the case with the tricyle, the steering of the Otto remains the same. This is because the steering of the tricycle depends on a kinematical, that of the Otto on a dynamical principle.

In another respect, no machine can approach the Otto; at almost any speed the rider can, if there is reason, instantly dismount, by which action he puts on the brakes, and the machine will save him from falling, stopping with him almost instantly. As is well known, we can move backward and forward, we can twist around and around in our own width, or can ride over bricks with impunity.

One objection to the machine is the difficulty of learning, which is considerable, but which presents no danger. This difficulty has been much exaggerated, for before the present powerful brake was applied it did require considerable skill to ride it down a steep hill. The way to do this must still be learnt, but it is now comparatively easy. For going down steep hills, the front steering tricycle is without a rival; I do not know what other machine will do this better than the Otto. Lastly, the foot straps, which would be a great advantage on any machine, if only they were safe, are not--though none but riders will believe it--in any way a source of danger on the Otto. Having ridden this machine for close upon 10,000 miles, I can speak with more authority on this point than can those who are not able to sit upon it for a moment.

The only disadvantage which the machine presents is the fact that it is impossible to remove the feet from the pedals while running, without dismounting; but though they must at all times follow the pedals, the Ottoist is not, as is generally thought, working when descending a hill.

The enthusiastic terms in which every one who has mastered the peculiarities of the Otto speaks of it would be considered as evidence in its favor, if we were not all considered by other cyclists to be in various stages of lunacy.

* * * * *

THE CANAL IRON WORKS, LONDON.

Some interest is awakened in engineering circles in London, just now, by the approaching close of the old engineering works so well known as the "Canal Ironworks," at the entrance to the Isle of Dogs, London, E. This notable establishment stands second in priority in London--that of Messrs. Maudslay, Sons & Field being the oldest--for the manufacture of marine engines. It was founded by the late Messrs. Seawards, above sixty years ago. Here was originated Seaward's hoisting "sheers" with the traveling back leg, a modern example of which, 100 feet high, in iron, stands on the wharf. An interesting tool, also, is the large vertical boring machine for largest size cylinders; Seaward spent £5,000 upon this, and it is certainly an admirable tool. There is also the large vertical slotting machine, with a stroke up to 5 feet 2 inches, a wonderfully powerful and compact machine. The extensive collection of screwing tackle is, perhaps, unsurpassed, and extends up to 8 inches diameter. There is a peculiar erecting shop roof, which will still repay examination.

* * * * *

MARINONI'S ROTARY PRINTING PRESS.

The greatest progress that has been made in recent years in the art of printing is in the invention of the high speed press provided with continuous paper.

Three French constructors, Messrs. Marinoni, Alauzet, and Derriey, have brought this kind of apparatus to such a degree of perfection that the majority of foreign journals having a large circulation buy their presses in France. We reproduce in Fig. 1 a perspective view of the Marinoni press, and in Fig. 2 a diagram showing the parts of the same. In order to give a complete description of it, we cannot do better than to reproduce the very interesting study that has been made of it by Mr. Monet, a civil engineer.

The roller, J (Fig. 2), is placed in the machine in the state in which it is received from the paper manufactory. The paper unwinds, runs over the rollers, e and e', which serve only for tautening it, and then passes between the two cylinders, A and B. The cylinder, A, carries the form, and B carries the blanket, and the paper thus receives its first impression. It afterward passes between the cylinders, A' and B', and receives an impression on the other side, the cylinder, A', carrying the form, and B' the blanket. Being now printed on both sides, it passes between the cylinders, KK', which cut it off and allow the sheet to slide between the cords of the rollers. These latter lead the sheets over the rollers, g h, on which they wind, one over the other, when the rollers, a a', are in the position shown by unbroken lines in the cut.

The part of the machine that holds the rollers, g h, and the different cords that wind over them, is the _accumulator_, and it is in this part of the press that the sheets accumulate, one over the other, to any number desired.

The size of the rollers, g h, and their distance apart are so regulated that when the sheet reaches the accumulator, it falls exactly on those that have preceded it. When the proper number of sheets is in the accumulator (4 or 5 being the number most employed for afterward facilitating the separation into packets on the receiving table), the two small rollers, a a', advance over the rack, N, and the sheets, instead of continuing to roll over into the accumulator, fall on the rack and are deposited by it upon the receiving table, O.

The rack having fallen twenty times, and deposited five sheets each time, or one hundred in all, the table moves in such a way as to prevent the sheets subsequently deposited from getting mixed with them. When the rack has fallen twenty times, the table returns to its initial position.

The distributing rollers, D, come in contact with the inking rollers, I, once during each revolution of the printing cylinders, and are mounted on racking levers provided with regulating screws that permit of easily regulating the amount of ink taken up. The supports of the inking rollers are movable and can be made to approach or recede from the distributing rollers, so as to still further vary the amount of ink taken up by them.

The distributing rollers supply the ink to a roller, E, of large diameter, which, having a backward and forward motion, begins to distribute the ink and to transmit it to a second roller, F, of the same diameter. This latter then spreads it over a metallic cylinder, G, which is of the same diameter as the printing cylinders, and against which revolve three distributing rollers, H, that have a backward and forward motion.

Between the cylindrical inking table, G, and the type cylinder, there are situated inking cylinders, T, of large diameter, that constantly take up ink from the inking table and distribute it over the types.

The machine here described, when designed for printing large sized journals, has cylinders whose circumference corresponds to the size of paper for two widths of pages, and whose length is sufficient to allow it to receive two forms. Each cylinder, then, carries four forms, or eight in all, and prints two complete copies at each revolution.

The large sheet cut off by the cylinders, K K', contains, then, two copies; and this sheet, on passing under the roller, f is again cut in two by a disk which separates it in a direction perpendicular to the cylinders.

To this press there may be added a mechanical folder of Mr. Marinoni's invention, capable of folding a journal five times.--_Annales Industrielles_.

* * * * *

CHENOT'S ECONOMIC FILTER PRESS.

Mr. E. Chenot, who is occupied in the manufacture of wine from dry grapes, has been led to devise a new style of filter, which by reason of its mode of action and its construction, he calls the "Economic Filter Press."

The apparatus, which is shown in the accompanying cut, consists of flat bags whose mouth may be at the top, as usual, or at the side. Through this orifice there is introduced a flat piece of wood or metal, which, like the bag, has an aperture through the center. The whole is suspended from a distributing pipe that is fixed at one end to the frame and is free at the other. This pipe is slotted beneath, and the pieces of wood or metal contain, opposite the slot, a number of small apertures that put the distributer in communication with the interior of the bags. Between these latter there are placed wire cloth frames which hold them in position and facilitate the flow of the filtered liquid. The cut shows the filter provided with a portion of its bags and frames. When all the frames are in place they are locked by causing the movable plate to move forward by means of two screws connected with an endless chain and actuated by a hand wheel. The pressure of this plate closes up the bags hermetically. Then, the feed cock being opened, the liquid flows into all the bags, deposits therein what it holds in suspension, and the clarified product flows to the inclined bottom of the filter and from thence to the exterior.

The apparatus may be supplied either through an upper reservoir, a juice elevator, or a pump. The discharge is proportional to the square root of the pressure. When the bags are full of residuum, the feed cock is closed, the filter is unscrewed, and the bags and frames are taken out. With fresh bags and the same frames, it is possible to at once set the apparatus in operation again.

Before the filter is taken apart, the residuum may be exhausted by washing it either with water or steam, or by pressure. To effect the operation by pressure, the pieces of wood or metal are removed, the mouths are closed by making a fold in the top of the bags, and the latter are then put back into the apparatus or into an ordinary press and submitted to another squeezing.

To render the maneuvering of it easier, the apparatus has been given a horizontal position.--_Revue Industrielle_.

* * * * *

[American Engineer]

STEEL CHAINS WITHOUT WELDING.

We take the following description, together with the illustrations, of a method and machine for making steel chain without welding, from our valued contemporary, _Le Genie Civil_, of Paris:

When we regard an ordinary oval-linked chain endwise, it presents itself in the form of a metal cross, and it was this that gave the cue to M. Oury, of the Government Arsenals, to construct chain without welding. By a series of matrices and punches, etc., he contrives, with small loss of metal, to model a chain out of cross-shaped steel bar.

Steel is the better material for such usage, from its homogeneity, both as to composition and strength.

Referring to the plate below, Figs. 1 to 10 explain the successive steps from the bar to the finished chain.

Fig. 1 shows in plan and section the steel bar, whose length may be some 40 feet, and which would make a chain say 50 feet long. The shape of the bar presents no difficulties in the way of rolling.

Figs. 2 and 3 give, in side elevations of the two faces and sections, the first rough form of the links. These first begin to take the exterior shape with the rounding of the angles.

The operations following, represented by Figs. 4 and 5, is the piercing of the center of the links, which can later be furnished with a stay for such chains as require special strength. The point now is to detach the links, which is accomplished by oblique piercings, as shown in Fig. 6. In the operation represented by Fig. 7, the oval shape is imparted to the link, and the operation finishes as shown in Fig. 8.

Actually, the links are circular and separate. This separation is retarded as much as possible, for it is plain that it is easier to operate a rigid bar than a chain, above all when the operation necessitates its being pushed forward.

By means of a good system of heating, analogous to that employed on the large parts entering into ship construction, it is hoped to perform a major part of the operations, of which we have given but an idea, at a single heat.

These operations require work on both faces alternately--this presents no difficulties; but what appears to us most difficult to realize is _continuous work_, the bar passing through several machines which successively impress upon it the steps of progress toward the finished chain. If the machines are end on to each other in a direct line, there will necessarily be a fixed place for each tool; the rough cut chain must accurately reach the point where another tool is ready to continue the modeling. This appears to us practically impossible, the more so as the elongation which the bar takes at each stamp varies with its initial diameter.

What is more admissible is that with one heat and in the same machine an operation could be performed on the two faces perpendicularly. The bar could then be taken from one furnace and put in another immediately, to pass at once to another machine to again undergo the operations following. The work could then be done rapidly, submitting the bar to several heats.

A few words on the tools as they exist.

The most important principle to note, and on which the different machines employed are designed, is this: The punches or matrices acting on the chain at its different points of progress are put in motion by spiral springs worked by means of tappets or cams distributed over the circumference of a cylinder, having a rotary movement imparted to it by pulleys and belts.

The figures on our plate show with sufficient clearness the working of one of these machines. It will be seen that the bar traverses through and through the machine for stamping, and that it can be disengaged for a reheating before passing to subsequent operations.

* * * * *

The bog peat of Mexico is now being used on a considerable scale as fuel for locomotives, stationary engines, smelting purposes, smiths' fires, and househould use. The peat is mixed with a proper proportion of bitumen, and is said not only to burn freely, and without smoke in much quantity, but to give a higher dynamic equivalent of heat than the same amount of wood.

* * * * *

THE BITTER SUBSTANCE OF HOPS.

[Footnote: _The Brewers' Guardian_, from the _Zeit. f. d. gesammte Brauwesen_.]

By DR. H. BUNGENER.

Little that is definite is known of the substance or substances to which the hop owes its bitterness. Lermer has succeeded, it is true, in separating from hops a crystallized colorless substance, insoluble in water, an alkaline solution of which has a marked bitter flavor, and which easily changes on exposure to the air, assuming a resinous form. According to Lermer, the formula of this substance is C_{32}H_{50}O_{7}; it possesses the properties of a weak acid and forms a characteristic copper salt, which is soluble in ether. This hop bitter is, however, produced from the hop by a very roundabout process, by treatment of the extract with alkalies; it is not therefore regarded by many as present in this form in the hop, and they hold that it is only produced by the action of the alkalies. On the other hand, however, Etti, by a complicated extracting process, but without using an alkali, succeeded in producing a bitter substance from hops, which is, however, soluble in water.

Several experiments convinced me that there really existed in hops a crystallizable substance, insoluble in water, the alcoholic and alkaline solution of which had a bitter flavor, in short, which possessed all the properties of Lermer's hop bitter acid. Petroleum ether is the best practical solvent in use for its isolation, as it does not dissolve the majority of the remaining constituents of the hop, especially the hop-resin, which they contain in considerable quantity. Still, the extraction of hop-bitter acid from hops is a troublesome and thankless job, the petroleum ether taking up certain substances which add greatly to the difficulty of purifying the crystals. On the other hand, we can readily and quickly attain our object, if we employ for our original material fresh lupuline from unsulphured hops.

The following process has furnished me the best results:

The lupuline is first freed from gross impurities (hop-seed leaves, etc.), and then covered with petroleum ether boiling at a low temperature (40° to 70°) in stoppered flasks. The mixture is shaken up from time to time. After twenty-four hours, by means of a Zullowsky filter immersed in the mass, and with the aid of a suction-pump, the dark brown solution is drawn off; then fresh ether is poured on to the lupuline, and it is allowed to stand for another twenty-four hours. After this process has been three times repeated, nearly everything the petroleum will dissolve has probably been extracted. The solutions are put together, and the petroleum ether distilled off _in vacuo_ at a low temperature, until there remains in the flask a dark brown sirup, which on cooling solidifies into a crystalline mass. This is pulverized and turned on to a filter composed of a large funnel, in which a smaller funnel covered with muslin is inserted. With the aid of a suction-pump, the greater portion of the thick, crude solution can be filtered through. There remains on the filter a highly colored crystalline "cake," which should be pulverized with a small quantity of petroleum ether and again filtered. After this operation has been repeated three or four times, we obtain an almost colorless mass, consisting of hop-bitter acid, contaminated by small quantities of a fatty substance, and a substance which I could not isolate, and which I had at first great trouble in separating from the hop-bitter acid.

If we do not wish to utilize this crude substance at once, it will be necessary to melt it in the water bath and pour it into a bottle under close seal, where it will at once crystallize and solidify. If it remains exposed to the atmosphere, it will soon become sticky and turn partly into resin. Six kilos of lupuline, which included a large proportion of sand, furnished 400 grammes of crude hop-bitter acid. The first experiments in crystallization with petroleum ether gave poor results; it is difficult to produce the acid pure in large quantities by this process, as a small quantity of the above substance obstinately clings to it, and it readily assumes a non-crystallizable form. Our object is more readily attained if we crystallize it once from alcohol, for which purpose we dissolve it in a little lukewarm alcohol, then quickly cool the solution; flakes of a fatty substance will be separated, which are removed by filtration with the aid of a suction-pump. Then we throw a few small crystals of the acid into the solution, and after a short time crystallization commences. As soon as it appears to be ended, the mother solution is removed with the aid of a platinum cone, and the crystals washed with a little cold alcohol. The alcoholic mother solution, which still contains the chief part of the bitter acid, must be quickly evaporated, and the residue consigned to a flask. The acid crystallized from the alcohol is then recrystallized several times from petroleum-ether. In order to quickly dissolve the bitter substance, it should be carefully melted in a flask, and double its volume of ether gradually added; on its cooling, we obtain beautiful prismatic crystals, which attain a length of 1 cm., and become perfectly pure after four or five crystallizations. The mother solutions must be speedily evaporated if we still wish to obtain crystals; after a time they will only furnish a resinous residue.

The hop-bitter acid melts at 92° to 93°. It is easily soluble in alcohol, ether, benzol, chloroform, sulphide of carbon, and vinegar; to a lesser extent in cold petroleum ether, and not at all in water.

In the analysis I obtained figures which correspond best with those calculated from the formula C_{25}H_{35}O_{4}.

Obtained.
Calculated. ------------------------^-----------------------
-----^----- 2. Crystal. 3. Crystal. 5. Crystal. 6. Crystal.
p.c. p.c. p.c. p.c. p.c. p.c. p.c.
C 75.19 74.79 74.83 74.9 75.04 75.05 75.07
H 8.77 8.97 8.90 8.85 8.87 8.83 8.80
O 16.04

If we shake up the ether solution of bitter substance with an aqueous solution of acetate of copper, the ether will assume a green color, and gradually deposits a green crystalline powder, a cupreous combination of the bitter acid. It is difficult to obtain in a pure state, as the solutions are readily subject to slight decomposition, accompanied by a small deposit of copper oxide. This combination is readily soluble in alcohol, to a lesser extent in ether, and is insoluble in water.

In the course of analysis, I obtained the following figures:

C 69.4 per cent. 69.3 per cent.
H 7.95 " 7.98 "
Cu 7.20 " 7.18 "

If we suppose that the copper combines with two molecules of hop-bitter acid, by the decomposition of one of its atoms, H, we obtain the formula C_{50}H_{68}O_{8}Cu. This combination will contain 69.87 per cent. C, 7.91 per cent. H, and 7.33 per cent. Cu. The figures obtained do not perfectly coincide with those calculated; it is nevertheless probable that the formula is correct, and the combined substance analyzed was not perfectly true.

I have already referred to the fact that solutions of hop-bitter acid, if left standing too long, assume a yellow color, and on evaporation leave only a yellow resinous residue. This, as its reaction shows, evinces a complete analogy with the crystallized acid. The dark-colored mother solution, from which the crystalline cakes of bitter acid are obtained, contains a large proportion of this resinous compound, which can be isolated by treatment with a weak soda-lye; this substance, like the crystallized acid, is soluble in alkalies, and can be precipitated from an alkaline solution by an acid. Old hops furnish far less crystallizable acid than new hops; from some samples I have been able to obtain only a few crystals; the remainder had been transformed into the resinous modification.

If pure hop-bitter acid be pulverized and exposed to the atmosphere, it soon turns yellow and the surface assumes a resinous consistency. At the same time, a more pronounced odor of fatty acids and aldehydes is apparent. Still more rapidly will this oxidation occur if a thin layer of an alcoholic solution of the acid is allowed to evaporate in the air. On the other hand, we can allow hop-oil to stand for days without its odor being perceptibly changed; it appears to me more than probable that the peculiar smell of old hops is due far more to the oxidation of the bitter substance than to the oxidation of oil.

Hop-bitter acid appears to possess the character of an aldehyde and of a weak acid; for the present I am not in a position to state its constitution more clearly. Most of the oxidizing processes have an energetic effect on it, forming also considerable quantities of valerianic acid.

The question as to whether the hop owes chiefly to this acid and its resinous modifications the property of imparting a pronounced bitter flavor to a solution, I must for the present leave unanswered. The acid and its isomer are both insoluble in water; they are, on the other hand, very readily dissolved in hop oil; they also furnish a tolerably bitter solution, if boiled for a long time in water, probably on their account of their gradual decomposition. I will not for the present go further into the subject, as I hope soon to be in a position to give more definite information.

* * * * *

ST. PAUL'S VICARAGE, FOREST HILL, KENT.

This vicarage, for the Rev. Frank Jones, has recently been completed from the designs of Mr. E.W. Mountford, A.R.I.B.A.; of 22 Buckingham Street, Strand, W. C., and Mr. H. D. Appleton, A.R.I.B.A., of the Wool Exchange, Coleman Street, E. C., who were the joint architects. The builder was Mr. William Robinson, of Lower Tooting, S. W. The walls are of yellow stock bricks, with red brick arches, quoins, etc., the gables being hung with Kentish tiles and the roofs covered with Broseley tiles. The internal joinery is of pitch pine.

The illustrations are from drawings by Mr. J. Stonier.--_The Architect_.

* * * * *

SOME ECONOMICAL PROCESSES CONNECTED WITH THE CLOTHWORKING INDUSTRY.

[Footnote: Read before the Society of Arts, London, May, 1884.]

By Dr. WILLIAM RAMSAY, Professor of Chemistry at University College, Bristol.

In this present age of scientific and technical activity, there is one branch which has, I think, been the subject of an article in the _Quarterly Journal of Science_. It is one which deserves attention. It was there termed "The Investigation of Residual Phenomena," and I can conceive no better title to express the idea. The investigator who first explores an unknown region is content if he can in some measure delineate its grand features--its rivers, its mountain chains, its plains; if he be a geologist, he attempts no more than broadly to observe its most important rock formations; if a botanist, its more striking forms of vegetation. So with the scientific investigator. The chemist or physicist who discovers a new law seldom succeeds in doing more than testing its general accuracy by experiments; it is reserved for his successors to note the divergence between his broad and sweeping generalization and particular instances which do not quite accord with it. So it was with Boyle's law that the volume of a gas varies in inverse ratio to the pressure to which it is exposed; so it is with the Darwinian theory, inasmuch as deterioration and degeneration play a part which was, perhaps, at first overlooked; and similar instances may be found in almost all pure sciences.

I conceive that the parallel from the technical point of view is a double one. For just as every technical process cannot be considered to be beyond improvement, there is always scope for technical investigation; but the true residual phenomena of which I would speak to-night are waste products. There is, I imagine, no manufacture in which every substance produced meets with a market. Some products are always allowed to run to waste, yet it is evident that every effort consistent with economy should be made to prevent such waste; and it has been frequently found that an attempt in this direction, though at first unsuccessful, has finally been worked into such a form as to remunerate the manufacturer.

It is my purpose to-night to bring under your notice methods by which saving can be effected in the cloth industry. I am aware that these methods have not much claim to novelty; but I also know that there are, unfortunately, few works where they are practiced.

The first of these relates to the saving and utilization of the soap used in wool scouring and milling. It is, perhaps, hardly necessary to explain that woolen goods are scoured by being run between rollers, after passing through a bath of soap, and this is continued for several hours, the cloth being repeatedly moistened with the lye, and repeatedly wrung out by the rollers. The process is analogous to ordinary washing; the soap dissolves the greasy film adhering to the fibers, and the "dirt" mechanically retained is thus loosened, and washed away. Now, in order to dissolve this greasy matter, a considerable amount of soap must be employed; and in the course of purification of the fabric, not merely what may be characterized as "dirt" is removed, but also short fibers, and various dye-stuffs with which the fabric has been dyed, many of which are partially soluble in alkaline water; moreover, it invariably happens that some dye does not combine with the fiber and mordant, thus becoming fixed, but merely incrusts the fiber; hence this portion is washed off when the retaining film of grease is removed from the fiber. The suds, therefore, after fulfilling this purpose, are no longer a pure solution of soap, but contain many foreign matters; and the problem is so to treat these suds as to recover the fat in some condition available for re-conversion into soap.

For this purpose wooden runnels are placed beneath the rollers, through which the cloth passes in the scouring machine, so as to collect the suds after they have been spent. These runnels lead to a wooden pipe or runnel, which receives the spent suds from all the scouring machines, and the whole of the waste, instead of being let off into the stream, polluting it, delivers into a tank or trough, which may also be constructed of wood, but, as it has to withstand the action of acid, is better lined with lead. This tank is necessarily proportioned in size to the number of scouring machines and the quantity of spent suds to be treated. When a sufficient quantity has collected, oil of vitriol, diluted with twice its bulk of water, is added, one workman pouring it in gradually while another stirs the contents of the tank vigorously. At short intervals, the liquid is tested by means of litmus paper, and when it shows a faint acid reaction, by turning the blue paper red, the addition of acid is stopped. The acid has then combined with the alkali of the soap, while the fatty acids formerly in combination with the alkali are liberated, and float to the surface of the liquid, carrying with them the impurities in the shape of short fibers and dye stuffs; the sand and heavier impurity, should any be present, sinks to the bottom.

After standing for some hours, the separation is complete. In order to separate the two layers, the tank is provided with an exit in the side, near the bottom, closed by a sluice or valve. This valve is opened, and the watery portion is allowed to escape into a sand filter bed.

The filter serves to retain any solid impurities which may still remain suspended in the water; but it will be found that the escaping water is nearly pure.

The dark brown fatty acid is mixed with a large amount of impurity, such as short wool fibers, burrs, sand, and dye stuffs washed from the wool. To remove water more completely, the semi-fluid mass is pumped from the tank, and delivered into hair-cloth filters; the liquid which drains from these bags finds its ways to the sand filters joining the drainage which formerly passed out from the tank through the sluice. After being turned over in the filter several times, the residue is transferred to canvas sacks. These sacks are placed in a filter press, where they are exposed to pressure while heated to a temperature sufficient to melt the fat. The solid impurities remain in the bags, while the fatty acids escape, and are received in a barrel or tank for the purpose. The fatty acids, when cold, are of a deep brown color, and of the consistency of butter. The residue is kept, and the method of treating it for the recovery of indigo will afterward be described.

The fatty acids are now ready for conversion into soap. It may here be remarked that, on distillation, they yield a nearly white fatty mass, which, when treated with soda-lye, is capable of yielding a perfectly white soap. But, for the clothworker's purpose, this purification is unnecessary.

The conversion into soap is a very simple matter. As the fats are acids--a mixture of palmitic, oleic, and stearic acids--and not the glycerine salts of these acids, like ordinary fats, soap is made by causing them directly to unite with caustic soda. The fats are melted in a copper, by means of a steam-jacket, or coil of steam-pipe in the copper, and the soda-lye is run in until complete union has taken place. The exact point of neutralization can easily be found by taking out a small sample after stirring, and dissolving it in some methylated spirits. A few drops of alcoholic tincture of phenol-phthalein are then added, and as soon as a faint red color appears, addition of soda is stopped. This shows that the fatty acids have been over-saturated. Addition of a little more fat renders them perfectly neutral, and the soap is then ladled out into wooden moulds, lined with loose sheets of zinc.

The resulting soap is of a brown color, but is perfectly adapted for the purpose of wool-scouring. It should here be mentioned that, in practice, the soap is always made somewhat alkaline; in point of fact, it contains about 2 per cent. of free alkali. This is found to assist in scouring; I presume that the free alkali forms a soap with the oil added to the wool during spinning, and if no free alkali be present, this oil would not be so thoroughly removed.

It will be noticed that in this simple method of soap-making, there is no salting out to separate the true soap from the watery solution of glycerine, for no glycerine is present. The apparatus may be of the simplest nature, and on any required scale, proportionate to the size of the mill. It is a process which requires no specially skilled labor; in any works some hand may be told off to conduct the process as occasion requires; and as a very large proportion of the fatty matter is recovered, the soap-bill is reduced to a very small fraction of the amount which would be paid were recovery not practiced. And lastly, the streams are not polluted; the only waste is a little sulphate of soda, which can hardly be regarded as a nuisance, inasmuch as it is a not unfrequent constituent of many natural waters.

Let us now return to the solid matter from which the fatty acids have been removed by pressure. This brown, earthly-looking cake consists of vegetable impurity washed off from the cloth, of short fibers, and of various dye stuffs. It is divided into two lots: That which contains indigo, and that which contains none, or which contains too small a quantity for profitable extraction. And it may here be remarked, that it is advisable to collect the suds from cloth dyed with indigo separate from that to dye which no indigo has been employed. The residue from indigo-dyed cloth has always a more or less blue shade, and if much indigo is present, the well-known copper-color is evident. Of course, the amount of indigo must greatly vary, but it may rise to 8 or 10 per cent. of the total weight of the refuse.

To recover the indigo from this refuse, the somewhat hard cakes are broken up, placed in a tank, and allowed to steep in water. When quite disintegrated, they are transferred to another tank--a barrel may be used for small quantities--and thus this refuse is exposed to the reducing action of copperas and lime. The indigo is converted into indigo-white, and is rendered soluble, and it oxidizes on the surface, forming a layer of blue froth on the top of the liquid, while the remainder of the impurities sinks. This process of reduction may last for twenty-four hours, and is helped by frequent stirring.

The indigo scum is preserved, and placed in filter cloths, where it is thoroughly washed with water two or three times. The residue which has sunk to the bottom is removed, dried, and forms a valuable manure, owing to the amount of the nitrogen which it contains. Its value may be increased by addition of weak vitriol, which exercises a decomposing action on the nitrogenous matter, forming with it sulphate of ammonia. The original residue from the filter-press, if it does not contain indigo, may be at once put to similar use.

In large works, which dye their own goods, it is well known that the "fermentation vat" is in general use for indigo-dyeing. But this vat requires constant superintendence, and must be kept in continual action; besides, it is successful only on a comparatively large scale. And, moreover, it requires skilled labor. Small works, or works in which dyeing is only occasionally practiced, find it more convenient to use Schützenberger and Lalande's process. Although this process is well known, a short description of it may not here be out of place.

The process depends on the reduction of indigo to indigo-white, or soluble indigo, by means of hyposulphite, or, as it is generally termed to avoid confusion with antichlore, rightly named thiosulphate of soda, hydrosulphite of soda. The formula of this substance is NaHSO_{2}, as distinguished from what is commonly known as hyposulphite of soda, Na_{2}S_{2}O_{3}. It is produced by the action of zinc-dust on the acid sulphite of soda. The zinc may be supposed to remove oxygen from the acid sulphite, NaHSO_{3}, giving hyposulphite, NaHS0_{2}. The reduction of the acid sulphite is best performed in a cask, which can be closed at the top, so as to avoid entrance of air. The acid sulphite of soda, at a strength of 50 or 60 Twaddell (specific gravity 1.26 to 1.3), is placed in the cask, and zinc-dust is added, with frequent stirring. The liquid is then mixed with milk of lime, and after again thoroughly stirring, the liquid is allowed to settle, and the clear is decanted into the dyeing-copper. The indigo, in the frothy state in which it is skimmed from the purifying barrels or tanks, is then added, with sufficient lime to dissolve it when it has been reduced. It is heated gently by a steam coil, to about 90° Fahr., and the goods are dyed in it. The colors obtained by means of this indigo are light in shade, and the goods must be dipped several times if dark shades are required. But it is found better in practice not to attempt to dye dark shades by this process; the ordinary indigo-vat is better adapted for such work. The object of not wasting indigo is sufficiently attained by employing it for the purpose to which it is best adapted. Of course the recovered indigo may be used in the ordinary manner. I merely mention the most convenient way of disposing of it in works where only a small quantity is recovered, and which do not practice dyeing on an extensive scale.

I have now to ask you to turn to a different subject, namely, the scouring of wool, not by the usual agent, water, but by a liquid, bisulphide of carbon, made by the action of sulphur vapor on red hot coke or charcoal.

This, again, is not wholly a new process, for various attempts have been made to dissolve out the yolk, or _suint_, or greasy matter from unwashed wool, as it comes from the back of the sheep. Fusel oil has been patented for this purpose. Carbon disulphide has also been patented, but, as will afterward be shown, the old method of removing it from the wool injured the color and quality of the fiber, so as to make the application of this scouring agent a failure.

Wool in its unwashed state contains a considerable proportion of what is termed _suint_. This consists of the fatty matter exuded as perspiration from the sheep, along with, or in some form of combination with, potash derived from the grass on which the sheep feed. _Suint_ was first investigated by Vauquelin. He obtained it by evaporating, after filtration, the water in which raw fleeces had been washed. The residue is of a brown color, and has a saline, bitter taste. On addition of an acid to its solution in water, it coagulates, and a fatty matter rises to the surface. It is, in fact, a potash soap, to a great extent containing carbonate and acetate of potash, along with chloride of potassium and lime, probably in combination also with fatty acids. It is usually mixed with sand and carbonate of lime.

In 1828, M. Chevreul, who is still alive in Paris, although nearly a century old, published an analysis of merino wool. It consisted of:

Per cent.
Pure wool 31.23
Soluble _suint_ 32.74
Insoluble 8.57
Earthy matter 27.46
------
100.00

It is easily seen that _suint_ forms a very important constituent of raw wool. Its proportion varies, of course, according to the nature of the pasture on which the sheep are fed, the climate, etc. Wool from Buenos Ayres, for example, contains much less than that analyzed by M. Chevreul; its amount is only 12 per cent. of the weight of the raw wool.

This _suint_ contains always about 52 per cent. of residue when ignited. The composition of this residue is:

Per cent.
Carbonate of potash 86.78
Chloride of potassium 6.18
Sulphate of potash 2.83
Silica, alumina, etc. 4.21
------
100.00

In 1859, MM. Maumene and Rogelet patented the use of the water in which wool has been washed as a source of potash, and at present the extraction of potash from _suint_ is practiced in France on a large scale. The wool is washed in a systematic manner, in casks, with cold water, which runs out of the last cask with specific gravity 1.1. These washings are evaporated to dryness, and the residue is calcined in iron retorts, the gas evolved being used for illuminating purposes. The remaining cinder, consisting of a mixture of charcoal and carbonate of potash, is treated with water, whereby the latter is dissolved out. The residue left on evaporation of this water consists largely--almost entirely--of white carbonate of potash. At present there are works at Rheims, Elboeuf, Fourmier, and Vervier, which yield about 1,000 tons of carbonate of potash annually. Now, only 15,000 tons are made per annum by Leblanc's process. In 1868, 62,000 tons of wool were imported into Britain from Australia alone, and from this 7,000 to 8,000 tons of carbonate of potash might have been recovered, the value of which is £260,000. Yet it was all wasted! And this estimate does not include the fats of the _suint_, which are worth an even greater sum.

Now, it is evident that there is here a profitable source of economy. So far as I am aware, no work in this country saves its washings. The water all goes to pollute the nearest river.

The use of carbon disulphide has again been introduced, and it is to be hoped with better success, for methods have been devised whereby the wool is not injured by it, but is even rendered better than when scoured by the old process of washing with carbonate of soda and water, or by soap. The process is due to Mr. Thomas J. Mullings. Briefly described, it consists in exposing the wool, placed in a hydro-extractor, to the action of bisulphide of carbon; the machine is then made to revolve, and the excess of solvent is expelled, carrying with it the fatty matters; the solvent finds its way into a tank, from which it flows into a still, heated with steam; the carbon disulphide, which boils at a very low temperature, distills over, and is again ready for use, while the residue in the still consists of _suint_ washed from the wool. To remove the last trace of carbon disulphide from the wool in the hydro-extractor, cold water is admitted, and when the wool is soaked, the machine again revolves. On expulsion of the water, the wool is ready for washing in the ordinary machines, but with cold water only instead of hot soapsuds.

The distinguishing features of Mr. Mullings' process are, method by which loss of carbon disulphide is avoided, and the extraction of that solvent by means of cold water. The apparatus consists of a hydro-extractor or centrifugal machine of special construction, fitted with a bell-shaped cover, which can be lifted into and out of position by means of a weighted lever. The rim of this cover fits into an annular cup filled with water, which surrounds the top of the machine, forming an effective seal or joint. Upon the spindle of this machine is suspended, as in ordinary forms of the hydro-extractor, a perforated basket, and in this basket is placed the wool to be treated. The cover being closed, the carbon disulphide is admitted, and passing through the wool, the greasy matter is dissolved, and along with the solvent enters a reservoir. The machine is now set in motion, and the bulk of the solvent is drawn off. Cold water is then admitted, and the machine being again caused to rotate, the whole of the bisulphide is expelled. It is a curious fact that, although wool soaks remarkably easily with carbon disulphide, and at once becomes wet, cold water expels and replaces almost all that liquid. This operation takes about twenty minutes, and at one operation about 1½ cwt. of raw wool may be treated. The wool is then washed in suitable washing machines of the ordinary type, but with cold water, no soap or alkali being employed. The bisulphide of carbon, mixed with water, flows into a reservoir, provided with diaphragms to prevent splashing, and consequent loss by evaporation. From its gravity it sinks, forming a layer below the water; it is then separated and recovered by distillation, and may be used in subsequent operations.

The point in which this process differs from the old and unsuccessful ones formerly tried, is in the expulsion of the carbon disulphide. It was imagined that it was necessary to expel it by means of heat or steam. Now, when wool moist with bisulphide is heated, it invariably turns yellow. No heat must, therefore, be employed. As already remarked, the solvent is expelled with cold water.

The residue, after distillation of the carbon disulphide, is a grayish colored, very viscous oily matter, still retaining a little bisulphide, as may be perceived from the smell. It has not the composition of ordinary _suint_, inasmuch as it contains no carbonate of potash, and indeed little mineral matter of any kind. A sample which I analyzed lost in drying 36.2 per cent., the loss consisting of water and carbon disulphide. It gave a residue on ignition amounting only to 1.6 per cent. of the original fatty matter, or 2.5 per cent. of the dried fat. The oil appears, from some experiments which I made, to be a mixture of a glycerine salt and a cholesterine salt of fatty acids. It distills without much decomposition, giving a brown-yellow oil, which fluoresces strongly, and has a somewhat pungent smell. The molecular weight was determined by saponification with alcoholic potash, and subsequent titration of the excess of potash employed. This was found to equal 546.3. This would correspond to a mixture of 18.7 parts of stearate, palmitate, and oleate of glycerine, with 81.3 parts of the same acids combined with cholesteryl. But this is largely conjecture. The boiling point of the oil is high, much above the range of a mercurial thermometer, so that it is difficult to gain an insight into its composition.

An objection which has been raised to this process is that the use of such an easily inflammable substance as bisulphide of carbon is attended by great risk of fire. Were the bisulphide to be exposed to free air, there might be force in this objection; but there is no reason why it should ever be removed from under a layer of water. The apparatus, to make all safe, should not be under the same roof as the mill; and no open fire need be used in the building set apart for it. It is easy to rotate the centrifugal machine by a belt from the mill, but better by a small engine attached, the power for which can be conducted by a small steam-pipe, and the distillation of the bisulphide can also be conducted without danger by the use of steam, as its boiling point is a very low one. The question may be naturally asked, "How do the wool and fabric made from the wool scoured by this process, compare with that scoured in the usual way?" To answer this question I may refer to a test made by Messrs. Isaac Holden & Co., at their works at Roubaix. A sample of wool was divided into two portions, one of which was scoured by the usual method, and the other by the turbine or Mullings' process. Skilled workers then span each sample to as fine a thread as possible. Now the thinness to which a wool can be spun is evidence of its power of cohesion--in other words, its strength. The weight of 1,000 meters of the wool cleaned by the new process bore to that scoured by the old process the proportion of 1,015 to 1,085, showing that a considerably finer thread had been produced. And in total quantity, 67.53 kilos. of the former corresponded to 71.77 kilos. of the latter, showing a proportionately less waste. Such fine yarn had never before been obtained from similar wool. The yarn of the soap-washed wool could not be spun, for it could not withstand the strain; whereas, that scoured by the new process gave an admirable thread.

Another test to which it was subjected may be cited. It is the custom in France, before the wool is scoured, to put it through a sorting process, by which all the short lengths are weeded out. On a quantity exceeding 11,000 kilogrammes, half of which was scoured by the turbine process, and half by the ordinary process, the former in scouring lost in weight 2 per cent. less than the latter, although the short length extracted from the moiety thus treated weighed only 10 kilogrammes, while that taken from the other weighed over 150 kilogrammes. This saving, even with the unequal treatment, amounted in value to from 30 to 40 centimes per kilogramme.

In order that the importance of this application may be realized, I shall conclude with some figures:

The raw wool imported into England, in the year 1882, amounted to 1,487,169 bales, its total value being about £22,000,000. The cost of washing this wool by the old process, with carbonate of soda, amounts to about ½d. per lb. of the raw material. The cost for the total quantity of wool imported is at least £1,214,000. But it is customary to wash wool with soap, especially for the combing trade, and the cost is then about 1d. per lb. The cost of scouring by the new process is about £1 5s. per ton, or 0.13d. per lb. Taking the least favorable comparison, were all the imported wool (home-grown wool is here left out of the calculation, for want of sufficient returns) cleansed by the turbine process, the actual saving would be £1,214,500 _minus_ £315,700, or nearly £900,000 per annum.