Chapter VIII: Front Matter (8)

-------------------------------------------------------------------------
| | | |Therm. AM|Therm. PM| | | |Varia-|Therm. |
| | | |---------|---------| | |Dis- |tion |at Noon.|
|Date|Latit.|Long.|Air|Water|Air|Water|Winds|Course|tance |of the|--------|
| | N. | W. | | | | | | | |Needle| | |
| | | | | | | | | |Miles.| West.| A.| W. |
|----|------|-----|---|-----|---|-----|-----|------|------|------|--------|
|Aug | | | | | | | | | | / |
| 20 |37 38 |38 6| 78| 76 | omitted |West |N ¼ W | 62 | | 77 | 75 |
| 21 |36 15 |38 26| 73| 74 | 78| 76 |W N W|S b W | 82 | | 77 | 75 |
| 22 |35 40 |38 44| 7 | 76 | 80| 77 |W b S|S S W | 38 | | 80 | 77 |
| 23 |35 35 |40 52| 7 | 77 | 78| 75 |North|W ¼ S | 100 | | omitted.|
| 24 |35 12 |41 31| 75| 73 | 75| 74 |W N W|S WbW | 41 | | 75 | 74 |
| 25 |35 40 |42 33| 79| 76 | 79| 76 |W b N|W NW¾N| 60 | | 80 | 76 |
| 26 |35 30 |42 44| 79| 76 | 80| 76 |S WbW|S W½S | 14 | | 80 | 76 |
| 27 |35 14 |43 23| 79| 77 | 81| 79 |West |W SW¼S| 38 | | 81 | 78 |
| 28 |34 23 |44 0| 7 | 76 | 78| 78 |N N E|S WbS | 60 | | 78 | 78 |
| 29 |34 12 |45 52| 77| 78 | 78| 78 |N E |W ¼ S | 94 | 8° 0| 79 | 78 |
| 30 |34 5 |48 31| 78| 78 | 78| 78 |East |W ½ S | 134 | | 78 | 78 |
| 31 |34 20 |51 4| 80| 79 | 81| 79 |East |W ¾ S | 129 | | 80 | 80 |
|Sep | | | | | | | | | | | | |
| 1 |34 20 |52 47| 81| 78 | omitted |S S W|W ¼ N | 86 | | 83 | 80 |
| 2 |34 55 |55 12| 81| 80 | 83| 80 |S W |WbN ½W| 125 | | 83 | 80 |
| 3 |35 30 |57 24| 83| 80 | 83| 80 |S WbS|WbN ½N| 114 | 6° 0| 84 | 81 |
| 4 |35 50 |59 1| 82| 80 | 83| 80 |S W½W|WbN ¼N| 82 | | 83 | 81 |
| 5 |35 55 |61 0| 81| 80 | 82| 81 |S S W|W ¼ N | 96 | | 82 | 81 |
| 6 |36 20 |62 30| 80| 81 | 79| 80 |N WbN|W b N | 75 | | 78 | 80 |
| 7 |34 50 |63 10| 87| 80 | 78| 81 |N WbN|S S W | 86 | | 78 | 81 |
| 8 |34 45 |64 40| 75| 79 | 75| 79 |North|W ¼ S | 74 | | 75 | 79 |
| 9 |35 43 |66 42| 75| 79 | 77| 73 |N E |W N W | 108 | | 78 | 80 |
| 10 |37 20 |68 40| 77| 73 | 77| 70 |E N E|N W | 126 | | 78 | 72 |
-------------------------------------------------------------------------

N.B. Longitude is reckoned from London, and the Thermometer is according to Fahrenheit.

OBSERVATIONS.

July 31. At one P.M. the Start bore WNW. distant six leagues.

August 1. The water appears luminous in the ship's wake.

---- 2. The temperature of the water is taken at eight in the
morning and at eight in the evening.

---- 6. The water appears less luminous.

---- 7. Formegas SW. dist 32½ deg. St. Mary's SW½S. 33 leagues.

---- 8. From this date the temperature of the water is taken at
eight in the morning and at six in the evening.

---- 10. Moonlight, which prevents the luminous appearance of the
water.

---- 11. A strong southerly current.

---- 12. Ditto. From this date the temperature of the air and water
was taken at noon, as well as morning and evening.

---- 16. Northerly current.

---- 19. First saw gulph weed.

---- 21. Southerly current.

---- 22. Again saw gulph weed.

---- 24. The water appeared luminous in a small degree before the
moon rose.

---- 29. No moon, yet very little light in the water.

---- 30. Much gulph weed to-day.

---- 31. Ditto.

Sept. 1. Ditto.

---- 2. A little more light in the water.

---- 4. No gulph weed to-day. More light in the water.

---- 5. Some gulph weed again.

---- 6. Little light in the water. A very hard thunder-gust in the
night.

---- 7. Little gulph weed.

---- 8. More light in the water. Little gulph weed.

---- 9. Little gulph weed. Little light in the water last evening.

---- 10. Saw some beds of rock-weed; and we were surprised to
observe the water six degrees colder by the thermometer than the
preceding noon.

This day (10th) the thermometer still kept descending, and at five
in the morning of the 11th, it was in water as low as 70, when
we struck soundings. The same evening the pilot came on board,
and we found our ship about five degrees of longitude a-head of
the reckoning, which our captain accounted for by supposing our
course to have been near the edge of the gulph stream, and thus
an eddy-current always in our favour. By the distance we ran from
Sept. 9, in the evening, till we struck soundings, we must have
then been at the western edge of the gulph stream, and the change
in the temperature of the water was probably owing to our suddenly
passing from that current, into the waters of our own climate.

On the 14th of August the following experiment was made. The
weather being perfectly calm, an empty bottle, corked very tight,
was sent down 20 fathoms, and it was drawn up still empty. It was
then sent down again 35 fathoms, when the weight of the water
having forced in the cork, it was drawn up full; the water it
contained was immediately tried by the thermometer, and found to be
70, which was six degrees colder than at the surface: the lead and
bottle were visible, but not very distinctly so, at the depth of
12 fathoms, but when only 7 fathoms deep, they were perfectly seen
from the ship. This experiment was thus repeated Sept. 11, when we
were in soundings of 18 fathoms. A keg was previously prepared with
a valve at each end, one opening inward, the other outward; this
was sent to the bottom in expectation that by the valves being both
open when going down, and both shut when coming up, it would keep
within it the water received at bottom. The upper valve performed
its office well, but the under one did not shut quite close, so
that much of the water was lost in hauling it up the ship's side.
As the water in the keg's passage upwards could not enter at the
top, it was concluded that what water remained in it was of that
near the ground, and on trying this by the thermometer, it was
found to be at 58, which was 12 degrees colder than at the surface.

_This last Journal was obligingly kept for me by Mr. J. Williams,
my fellow-passenger in the London Packet, who made all the
experiments with great exactness._

TO MR. O. N[36].

_On the Art of Swimming._

[No date.]

DEAR SIR,

I cannot be of opinion with you that it is too late in life for you to learn to swim. The river near the bottom of your garden affords a most convenient place for the purpose. And as your new employment requires your being often on the water, of which you have such a dread, I think you would do well to make the trial; nothing being so likely to remove those apprehensions as the consciousness of an ability to swim to the shore, in case of an accident, or of supporting yourself in the water till a boat could come to take you up.

I do not know how far corks or bladders may be useful in learning to swim, having never seen much trial of them. Possibly they may be of service in supporting the body while you are learning what is called the stroke, or that manner of drawing in and striking out the hands and feet that is necessary to produce progressive motion. But you will be no swimmer till you can place some confidence in the power of the water to support you; I would therefore advise the acquiring that confidence in the first place; especially as I have known several who, by a little of the practice necessary for that purpose, have insensibly acquired the stroke, taught as it were by nature.

The practice I mean is this. Chusing a place where the water deepens gradually, walk coolly into it till it is up to your breast, then turn round, your face to the shore, and throw an egg into the water between you and the shore. It will sink to the bottom, and be easily seen there, as your water is clear. It must lie in water so deep as that you cannot reach it to take it up but by diving for it. To encourage yourself in order to do this, reflect that your progress will be from deeper to shallower water, and that at any time you may, by bringing your legs under you and standing on the bottom, raise your head far above the water. Then plunge under it with your eyes open, throwing yourself towards the egg, and endeavouring by the action of your hands and feet against the water to get forward till within reach of it. In this attempt you will find, that the water buoys you up against your inclination; that it is not so easy a thing to sink as you imagined; that you cannot but by active force get down to the egg. Thus you feel the power of the water to support you, and learn to confide in that power; while your endeavours to overcome it, and to reach the egg, teach you the manner of acting on the water with your feet and hands, which action is afterwards used in swimming to support your head higher above water, or to go forward through it.

I would the more earnestly press you to the trial of this method, because, though I think I satisfied you that your body is lighter than water, and that you might float in it a long time with your mouth free for breathing, if you would put yourself in a proper posture, and would be still and forbear struggling; yet till you have obtained this experimental confidence in the water, I cannot depend on your having the necessary presence of mind to recollect that posture and the directions I gave you relating to it. The surprize may put all out of your mind. For though we value ourselves on being reasonable knowing creatures, reason and knowledge seem on such occasions to be of little use to us; and the brutes to whom we allow scarce a glimmering of either, appear to have the advantage of us.

I will, however, take this opportunity of repeating, those particulars to you, which I mentioned in our last conversation, as, by perusing them at your leisure, you may possibly imprint them so in your memory as on occasion to be of some use to you.

1. That though the legs, arms, and head, of a human body, being solid parts, are specifically something heavier than fresh water, yet the trunk, particularly the upper part, from its hollowness, is so much lighter than water, as that the whole of the body taken together is too light to sink wholly under water, but some part will remain above, until the lungs become filled with water, which happens from drawing water into them instead of air, when a person in the fright attempts breathing while the mouth and nostrils are under water.

2. That the legs and arms are specifically lighter than salt water, and will be supported by it, so that a human body would not sink in salt-water, though the lungs were filled as above, but from the greater specific gravity of the head.

3. That therefore a person throwing himself on his back in salt water, and extending his arms, may easily lie so as to keep his mouth and nostrils free for breathing; and by a small motion of his hands may prevent turning, if he should perceive any tendency to it.

4. That in fresh water, if a man throws himself on his back, near the surface, he cannot long continue in that situation but by proper action of his hands on the water. If he uses no such action, the legs and lower part of the body will gradually sink till he comes into an upright position, in which he will continue suspended, the hollow of the breast keeping the head uppermost.

5. But if, in this erect position, the head is kept upright above the shoulders, as when we stand on the ground, the immersion will, by the weight of that part of the head that is out of water, reach above the mouth and nostrils, perhaps a little above the eyes, so that a man cannot long remain suspended in water with his head in that position.

6. The body continuing suspended as before, and upright, if the head be leaned quite back, so that the face looks upwards, all the back part of the head being then under water, and its weight consequently in a great measure supported by it, the face will remain above water quite free for breathing, will rise an inch higher every inspiration, and sink as much every expiration, but never so low as that the water may come over the mouth.

7. If therefore a person unacquainted with swimming and falling accidentally into the water, could have presence of mind sufficient to avoid struggling and plunging, and to let the body take this natural position, he might continue long safe from drowning till perhaps help would come. For as to the cloaths, their additional weight while immersed is very inconsiderable, the water supporting it though, when he comes out of the water, he would find them very heavy indeed.

But, as I said before, I would not advise you or any one to depend on having this presence of mind on such an occasion, but learn fairly to swim; as I wish all men were taught to do in their youth; they would, on many occurrences, be the safer for having that skill, and on many more the happier, as freer from painful apprehensions of danger, to say nothing of the enjoyment in so delightful and wholesome an exercise. Soldiers particularly should, methinks, all be taught to swim; it might be of frequent use either in surprising an enemy, or saving themselves. And if I had now boys to educate, I should prefer those schools (other things being equal) where an opportunity was afforded for acquiring so advantageous an art, which once learned is never forgotten.

I am, Sir, &c.

B. FRANKLIN.

FOOTNOTE:

[36] Oliver Neale. _Editor._

ON THE SAME SUBJECT,

_In Answer to some Enquiries of M. Dubourg[37]._

**** I am apprehensive that I shall not be able to find leisure for making all the disquisitions and experiments which would be desirable on this subject. I must, therefore, content myself with a few remarks.

The specific gravity of some human bodies, in comparison to that of water, has been examined by Mr. Robinson, in our Philosophical Transactions, volume 50, page 30, for the year 1757. He asserts, that fat persons with small bones float most easily upon the water.

The diving-bell is accurately described in our Transactions.

When I was a boy, I made two oval pallets, each about ten inches long, and six broad, with a hole for the thumb, in order to retain it fast in the palm of my hand. They much resembled a painter's pallets. In swimming I pushed the edges of these forward, and I struck the water with their flat surfaces as I drew them back. I remember I swam faster by means of these pallets, but they fatigued my wrists. I also fitted to the soles of my feet a kind of sandals; but I was not satisfied with them, because I observed that the stroke is partly given by the inside of the feet and the ancles, and not entirely with the soles of the feet.

We have here waistcoats for swimming, which are made of double sail-cloth, with small pieces of cork quilted in between them.

I know nothing of the _scaphandre_ of M. de la Chapelle.

I know by experience, that it is a great comfort to a swimmer, who has a considerable distance to go, to turn himself sometimes on his back, and to vary in other respects the means of procuring a progressive motion.

When he is seized with the cramp in the leg, the method of driving it away is to give to the parts affected a sudden, vigorous and violent shock; which he may do in the air as he swims on his back.

During the great heats of summer there is no danger in bathing, however warm we may be, in rivers which have been thoroughly warmed by the sun. But to throw oneself into cold spring water, when the body has been heated by exercise in the sun, is an imprudence which may prove fatal. I once knew an instance of four young men, who, having worked at harvest in the heat of the day, with a view of refreshing themselves plunged into a spring of cold water: two died upon the spot, a third the next morning, and the fourth recovered with great difficulty. A copious draught of cold water, in similar circumstances, is frequently attended with the same effect in North America.

The exercise of swimming is one of the most healthy and agreeable in the world. After having swam for an hour or two in the evening, one sleeps coolly the whole night, even during the most ardent heat of summer. Perhaps the pores being cleansed, the insensible perspiration increases and occasions this coolness. It is certain that much swimming is the means of stopping a diarrhœa, and even of producing a constipation. With respect to those who do not know how to swim, or who are affected with a diarrhœa at a season which does not permit them to use that exercise, a warm bath, by cleansing and purifying the skin, is found very salutary, and often effects a radical cure. I speak from my own experience, frequently repeated, and that of others to whom I have recommended this.

You will not be displeased if I conclude these hasty remarks by informing you, that as the ordinary method of swimming is reduced to the act of rowing with the arms and legs, and is consequently a laborious and fatiguing operation when the space of water to be crossed is considerable; there is a method in which a swimmer may pass to great distances with much facility, by means of a sail. This discovery I fortunately made by accident, and in the following manner.

When I was a boy I amused myself one day with flying a paper kite; and approaching the bank of a pond, which was near a mile broad, I tied the string to a stake, and the kite ascended to a very considerable height above the pond, while I was swimming. In a little time, being desirous of amusing myself with my kite, and enjoying at the same time the pleasure of swimming, I returned; and loosing from the stake the string with the little stick which was fastened to it, went again into the water, where I found, that, lying on my back and holding the stick in my hands, I was drawn along the surface of the water in a very agreeable manner. Having then engaged another boy to carry my clothes round the pond, to a place which I pointed out to him on the other side, I began to cross the pond with my kite, which carried me quite over without the least fatigue, and with the greatest pleasure imaginable. I was only obliged occasionally to halt a little in my course, and resist its progress, when it appeared that, by following too quick, I lowered the kite too much; by doing which occasionally I made it rise again. I have never since that time practised this singular mode of swimming, though I think it not impossible to cross in this manner from Dover to Calais. The packet-boat, however, is still preferable. ****

B. FRANKLIN.

FOOTNOTE:

[37] This and the four following extracts of letters to M. Dubourg, are re-translated from the French edition of Dr. Franklin's works. _Editor._

TO M. DUBOURG.

_On the free Use of Air._

_London, July 28, 1760._

**** I greatly approve the epithet which you give, in your letter of the 8th of June, to the new method of treating the small-pox, which you call the _tonic_ or bracing method; I will take occasion, from it, to mention a practice to which I have accustomed myself. You know the cold bath has long been in vogue here as a tonic; but the shock of the cold water has always appeared to me, generally speaking, as too violent, and I have found it much more agreeable to my constitution to bathe in another element, I mean cold air. With this view I rise almost every morning, and sit in my chamber without any clothes whatever, half an hour or an hour, according to the season, either reading or writing. This practice is not in the least painful, but, on the contrary, agreeable; and if I return to bed afterwards, before I dress myself, as sometimes happens, I make a supplement to my night's rest of one or two hours of the most pleasing sleep that can be imagined. I find no ill consequences whatever resulting from it, and that at least it does not injure my health, if it does not in fact contribute much to its preservation. I shall therefore call it for the future a _bracing_ or _tonic_ bath. ****

B. FRANKLIN.

_On the Causes of Colds._

_March 10, 1773._

**** I shall not attempt to explain why damp clothes occasion colds, rather than wet ones, because I doubt the fact; I imagine that neither the one nor the other contribute to this effect, and that the causes of colds are totally independent of wet and even of cold. I propose writing a short paper on this subject, the first moment of leisure I have at my disposal. In the mean time I can only say, that having some suspicions that the common notion, which attributes to cold the property of stopping the pores and obstructing perspiration, was ill founded, I engaged a young physician, who is making some experiments with Sanctorius's balance, to estimate the different proportions of his perspiration, when remaining one hour quite naked, and another warmly clothed. He pursued the experiment in this alternate manner for eight hours successively, and found his perspiration almost double during those hours in which he was naked. ****

B. FRANKLIN.

_Dr. Stark_[38].

_May 4, 1773._

**** The young physician whom I mentioned is dead, and all the notes which he had left of his curious experiments are by some accident lost between our friends Sir John Pringle and Dr. Huck (Saunders); but these gentlemen, if the papers cannot be recovered, it is to be presumed, will repeat the experiments themselves ****

B. FRANKLIN.

_Dr. Lettsom._

_London, August 30, 1769._

**** This letter will be forwarded to you by Dr. Lettsom, a young American physician of much merit, and one of the peaceable sect of Quakers: you will therefore at least regard him as a curiosity, even though you should have embraced all the opinions of the majority of your countrymen concerning these people ****

B. FRANKLIN.

FROM DR. ----[39] OF BOSTON, TO BENJAMIN FRANKLIN, ESQ. OF PHILADELPHIA.

_Respecting the Number of Deaths in Philadelphia by Inoculation._

_Boston, Aug. 3, 1752._

SIR,

This comes to you on account of Dr. Douglass: he desired me to write to you for what you know of the number that died of the inoculation in Philadelphia, telling me he designed to write something on the small-pox shortly. We shall both be obliged to you for a word on this affair.

The chief particulars of our visitation, you have in the public prints. But the less degree of mortality than usual in the common way of infection, seems chiefly owing to the purging method designed to prevent the secondary fever; a method first begun and carried on in this town, and with success beyond expectation. We lost one in eleven one-sixth, but had we been experienced in this way, at the first coming of the distemper, probably the proportion had been but one in thirteen or fourteen. In the year 1730 we lost one in nine, which is more favourable than ever before with us. The distemper pretty much the same then as now, but some circumstances not so kind this time.

If there be any particulars which you want to know, please to signify what they are, and I shall send them.

The number of our inhabitants decreases[40]. On a strict inquiry, the overseers of the poor find but fourteen thousand one hundred and ninety Whites, and one thousand five hundred and forty-four Blacks, including those absent, on account of the small-pox, many of whom, it is probable, will never return.

I pass this opportunity without any particulars of my old theme. One thing, however, I must mention, which is, that perhaps my last letters contained something that seemed to militate with your doctrine of the _Origin_, &c. But my design was only to relate the phenomena as they appeared to me. I have received so much light and pleasure from your writings, as to prejudice me in favour of every thing from your hand, and leave me only liberty to observe, and a power of dissenting when some great probability might oblige me: and if at any time that be the case, you will certainly hear of it.

I am, Sir, &c.

FOOTNOTES:

[38] The works of Dr. Stark, including the experiments alluded to, have since been published. _Editor._

[39] Dr. Perkins. _Editor._

[40] Boston is an old town, and was formerly the seat of all the trade of the country, that was carried on by sea. New towns, and ports, have, of late, divided the trade with it, and diminished its inhabitants, though the inhabitants of the country, in general, have greatly increased.

FROM BENJAMIN FRANKLIN, ESQ. OF PHILADELPHIA.

_In Answer to the preceding._

_Philadelphia, Aug. 13, 1752._

SIR,

I received your favour of the 3d instant. Some time last winter I procured from one of our physicians an account of the number of persons inoculated during the five visitations of the small-pox we have had in twenty-two years; which account I sent to Mr. W. V. of your town, and have no copy. If I remember right, the number exceeded eight hundred, and the deaths were but four. I suppose Mr. V. will show you the account, if he ever received it. Those four were all that our doctors allow to have died of the small-pox by inoculation, though I think there were two more of the inoculated who died of the distemper; but the eruptions appearing soon after the operation, it is supposed they had taken the infection before, in the common way.

I shall be glad to see what Dr. Douglass may write on the subject. I have a French piece printed at Paris, 1724, entitled, _Observations sur la Saignée du Pied, et sur la Purgation au commencement de la Petite Verole, & Raisons de doubte contre l' Inoculation._--A letter of the doctor's is mentioned in it. If he or you have it not, and desire to see it, I will send it.--Please to favour me with the particulars of your purging method, to prevent the secondary fever.

I am indebted for your preceding letter, but business sometimes obliges one to postpone philosophical amusements. Whatever I have wrote of that kind, are really, as they are entitled, but _Conjectures_ and _Suppositions_; which ought always to give place, when careful observation militates against them. I own I have too strong a penchant to the building of hypotheses; they indulge my natural indolence: I wish I had more of your patience and accuracy in making observations, on which, alone, true philosophy can be founded. And, I assure you, nothing can be more obliging to me, than your kind communication of those you make, however they may disagree with my pre-conceived notions.

I am sorry to hear that the number of your inhabitants decreases. I some time since, wrote a small paper of _Thoughts on the peopling of Countries_[41], which, if I can find, I will send you, to obtain your sentiments. The favourable opinion you express of my writings, may, you see, occasion you more trouble than you expected from,

Sir, yours, &c.

B. FRANKLIN.

FOOTNOTE:

[41] This paper will be found in a subsequent part of the present volume. _Editor._

TO BENJAMIN VAUGHAN, ESQ.

_On the Effects of Lead upon the human Constitution[42]._

_Philadelphia, July 31, 1786._

DEAR FRIEND,

I recollect that when I had last the pleasure of seeing you at Southampton, now a twelvemonth since, we had some conversation on the bad effects of lead taken inwardly; and that at your request I promised to send you in writing a particular account of several facts I then mentioned to you, of which you thought some good use might be made. I now sit down to fulfil that promise.

The first thing I remember of this kind was a general discourse in Boston when I was a boy, of a complaint from North Carolina against New-England rum, that it poisoned their people, giving them the dry-belly-ach, with a loss of the use of their limbs. The distilleries being examined on the occasion, it was found, that several of them used leaden still-heads and worms, and the physicians were of opinion, that the mischief was occasioned by that use of lead. The legislature of Massachussetts thereupon passed an act, prohibiting, under severe penalties, the use of such still-heads and worms hereafter.

In 1724, being in London, I went to work in the printing-house of Mr. Palmer, Bartholomew-close, as a compositor. I there found a practice, I had never seen before, of drying a case of types (which are wet in distribution) by placing it sloping before the fire.

I found this had the additional advantage, when the types were not only dried but heated, of being comfortable to the hands working over them in cold weather. I therefore sometimes heated my case when the types did not want drying. But an old workman observing it advised me not to do so, telling me I might lose the use of my hands by it, as two of our companions had nearly done, one of whom, that used to earn his guinea a week, could not then make more than ten shillings, and the other, who had the dangles, but seven and sixpence. This, with a kind of obscure pain, that I had sometimes felt, as it were, in the bones of my hand when working over the types made very hot, induced me to omit the practice. But talking afterwards with Mr. James, a letter-founder in the same Close, and asking him if his people, who worked over the little furnaces of melted metal, were not subject to that disorder; he made light of any danger from the effluvia, but ascribed it to particles of the metal swallowed with their food by slovenly workmen, who went to their meals after handling the metal, without well washing their fingers, so that some of the metalline particles were taken off by their bread and eaten with it. This appeared to have some reason in it. But the pain I had experienced made me still afraid of those effluvia.

Being in Derbyshire at some of the furnaces for smelting of lead ore, I was told, that the smoke of those furnaces was pernicious to the neighbouring grass and other vegetables; but I do not recollect to have heard any thing of the effect of such vegetables eaten by animals. It may be well to make the enquiry.

In America I have often observed, that on the roofs of our shingled-houses, where moss is apt to grow in northern exposures, if there be any thing on the roof painted with white lead, such as balusters, or frames of dormant windows, &c. there is constantly a streak on the shingles from such paint down to the eaves, on which no moss will grow, but the wood remains constantly clean and free from it. We seldom drink rain-water that fall on our houses; and if we did, perhaps the small quantity of lead descending from such paint might not be sufficient to produce any sensible ill-effect on our bodies. But I have been told of a case in Europe, I forget the place, where a whole family was afflicted with what we call the dry-belly-ach, or _colica pictorum_, by drinking rain-water. It was at a country-seat, which, being situated too high to have the advantage of a well, was supplied with water from a tank, which received the water from the leaded roofs. This had been drank several years without mischief, but some young trees planted near the house growing up above the roof, and shedding their leaves upon it, it was supposed, that an acid in those leaves had corroded the lead they covered, and furnished the water of that year with its baneful particles and qualities.

When I was in Paris with Sir John Pringle in 1767, he visited _La Charité_, an hospital particularly famous for the cure of that malady, and brought from thence a pamphlet, containing a list of the names of persons, specifying their professions or trades, who had been cured there. I had the curiosity to examine that list, and found, that all the patients were of trades, that some way or other use or work in lead; such as plumbers, glaziers, painters, &c. excepting only two kinds, stone-cutters and soldiers. In them, I could not reconcile it to my notion, that lead was the cause of that disorder. But on my mentioning it to a physician of that hospital, he informed me, that the stone-cutters are continually using melted lead to fix the ends of iron balustrades in stone; and that the soldiers had been employed by painters as labourers in grinding of colours.

This, my dear friend, is all I can at present recollect on the subject. You will see by it, that the opinion of this mischievous effect from lead, is at least above sixty years old; and you will observe with concern how long a useful truth may be known and exist, before it is generally received and practised on.

I am, ever, yours most affectionately,

B. FRANKLIN.

FOOTNOTE:

[42] This letter is taken from a work by Dr. John Hunter, entitled _Observations on the Diseases of the Army_. _Editor._

TO M. DUBOURG[43].

_Observations on the prevailing Doctrines of Life and Death._

**** Your observations on the causes of death, and the experiments which you propose for recalling to life those who appear to be killed by lightning, demonstrate equally your sagacity and your humanity. It appears, that the doctrines of life and death, in general, are yet but little understood.

A toad buried in sand will live, it is said, till the sand becomes petrified: and then, being inclosed in the stone, it may still live for we know not how many ages. The facts which are cited in support of this opinion are too numerous, and too circumstantial, not to deserve a certain degree of credit. As we are accustomed to see all the animals, with which we are acquainted, eat and drink, it appears to us difficult to conceive, how a toad can be supported in such a dungeon: but if we reflect, that the necessity of nourishment, which animals experience in their ordinary state, proceeds from the continual waste of their substance by perspiration, it will appear less incredible, that some animals in a torpid state, perspiring less because they use no exercise, should have less need of aliment; and that others, which are covered with scales or shells, which stop perspiration, such as land and sea-turtles, serpents, and some species of fish, should be able to subsist a considerable time without any nourishment whatever.--A plant, with its flowers, fades and dies immediately, if exposed to the air without having its root immersed in a humid soil, from which it may draw a sufficient quantity of moisture to supply that which exhales from its substance and is carried off continually by the air. Perhaps, however, if it were buried in quicksilver, it might preserve for a considerable space of time its vegetable life, its smell and colour. If this be the case, it might prove a commodious method of transporting from distant countries those delicate plants, which are unable to sustain the inclemency of the weather at sea, and which require particular care and attention. I have seen an instance of common flies preserved in a manner somewhat similar. They had been drowned in Madeira wine, apparently about the time when it was bottled in Virginia, to be sent hither (to London). At the opening of one of the bottles, at the house of a friend where I then was, three drowned flies fell into the first glass that was filled. Having heard it remarked, that drowned flies were capable of being revived by the rays of the sun, I proposed making the experiment upon these: they were therefore exposed to the sun upon a sieve, which had been employed to strain them out of the wine. In less than three hours, two of them began by degrees to recover life. They commenced by some convulsive motions of the thighs, and at length they raised themselves upon their legs, wiped their eyes with their fore-feet, beat and brushed their wings with their hind-feet, and soon after began to fly, finding themselves in Old England, without knowing how they came thither. The third continued lifeless till sunset, when, losing all hopes of him, he was thrown away.

I wish it were possible, from this instance, to invent a method of embalming drowned persons, in such a manner that they may be recalled to life at any period, however distant; for having a very ardent desire to see and observe the state of America an hundred years hence, I should prefer to any ordinary death, the being immersed in a cask of Madeira wine, with a few friends till that time, to be then recalled to life by the solar warmth of my dear country! But since in all probability we live in an age too early and too near the infancy of science, to hope to see such an art brought in our time to its perfection, I must for the present content myself with the treat, which you are so kind as to promise me, of the resurrection of a fowl or a turkey-cock.

I am, &c.

B. FRANKLIN.

FOOTNOTE:

[43] This letter is translated from the French edition of Dr. Franklin's works. It has no date, but the letter to which it is an answer is dated 15th April, 1773.

_An Account of the new-invented Pensylvanian Fire-Places: wherein
their Construction and Manner of Operation is particularly
explained; their Advantages above every other Method of warming
Rooms demonstrated; and all Objections that have been raised
against the Use of them answered and obviated. With Directions for
putting them up, and for using them to the best Advantage. And a
Copper-Plate, in which the several parts of the Machine are exactly
laid down, from a Scale of Equal Parts._

BY B. FRANKLIN.

(First printed at Philadelphia in 1745.)

In these northern colonies the inhabitants keep fires to sit by generally seven months in the year; that is, from the beginning of October, to the end of April; and, in some winters, near eight months, by taking in part of September and May.

Wood, our common fuel, which within these hundred years might be had at every man's door, must now be fetched near one hundred miles to some towns, and makes a very considerable article in the expence of families.

As therefore so much of the comfort and conveniency of our lives, for so great a part of the year, depends on the article of _fire_; since fuel is become so expensive, and (as the country is more cleared and settled) will of course grow scarcer and dearer, any new proposal for saving the wood, and for lessening the charge, and augmenting the benefit of fire, by some particular method of making and managing it, may at least be thought worth consideration.

The new fire-places are a late invention to that purpose, of which this paper is intended to give a particular account.

That the reader may the better judge whether this method of managing fire has any advantage over those heretofore in use, it may be proper to consider both the old and new methods separately and particularly, and afterwards make the comparison.

In order to this, it is necessary to understand well, some few of the properties of air and fire, viz.

1. Air is rarefied by _heat_, and condensed by _cold_, _i. e._ the same quantity of air takes up more space when warm than when cold. This may be shown by several very easy experiments. Take any clear glass bottle (a Florence flask stript of the straw is best) place it before the fire, and as the air within is warmed and rarefied, part of it will be driven out of the bottle; turn it up, place its mouth in a vessel of water, and remove it from the fire; then, as the air within cools and contracts, you will see the water rise in the neck of the bottle, supplying the place of just so much air as was driven out. Hold a large hot coal near the side of the bottle, and as the air within feels the heat, it will again distend and force out the water.--Or, fill a bladder not quite full of air, tie the neck tight, and lay it before a fire as near as may be without scorching the bladder; as the air within heats, you will perceive it to swell and fill the bladder, till it becomes tight, as if full blown: remove it to a cool place, and you will see it fall gradually, till it becomes as lank as at first.

2. Air rarefied and distended by heat is[44] specifically lighter than it was before, and will rise in other air of greater density. As wood, oil, or any other matter specifically lighter than water, if placed at the bottom of a vessel of water, will rise till it comes to the top; so rarefied air will rise in common air, till it either comes to air of equal weight, or is by cold reduced to its former density.

A fire then being made in any chimney, the air over the fire is rarefied by the heat, becomes lighter, and therefore immediately rises in the funnel, and goes out; the other air in the room (flowing towards the chimney) supplies its place, is rarefied in its turn, and rises likewise; the place of the air thus carried out of the room, is supplied by fresh air coming in through doors and windows, or, if they be shut, through every crevice with violence, as may be seen by holding a candle to a key-hole: If the room be so tight as that all the crevices together will not supply so much air as is continually carried off, then, in a little time, the current up the funnel must flag, and the smoke being no longer driven up, must come into the room.

1. Fire (_i. e._ common fire) throws out light, heat, and smoke (or fume.) The two first move in right lines, and with great swiftness, the latter is but just separated from the fuel, and then moves only as it is carried by the stream of rarefied air: and without a continual accession and recession of air, to carry off the smoaky fumes, they would remain crouded about the fire, and stifle it.

2. Heat may be separated from the smoke as well as from the light, by means of a plate of iron, which will suffer heat to pass through it without the others.

3. Fire sends out its rays of heat as well as rays of light, equally every way; but the greatest sensible heat is over the fire, where there is, besides the rays of heat shot upwards, a continual rising stream of hot air, heated by the rays shot round on every side.

These things being understood, we proceed to consider the fire-places heretofore in use, _viz._

1. The large open fire-places used in the days of our fathers, and still generally in the country, and in kitchens.

2. The newer-fashioned fire-places, with low breasts, and narrow hearths.

3. Fire-places with hollow backs, hearths, and jams of iron (described by M. Gauger, in his tract entitled, _La Mechanique de Feu_) for warming the air as it comes into the room.

4. The Holland stoves, with iron doors opening into the room.

5. The German stoves, which have no opening in the room where they are used, but the fire is put in from some other room, or from without.

6. Iron pots, with open charcoal fires, placed in the middle of a room.

1. The first of these methods has generally the conveniency of two warm seats, one in each corner; but they are sometimes too hot to abide in, and, at other times, incommoded with the smoke; there is likewise good room for the cook to move, to hang on pots, &c. Their inconveniencies are, that they almost always smoke, if the door be not left open; that they require a large funnel, and a large funnel carries off a great quantity of air, which occasions what is called a strong draft to the chimney, without which strong draft the smoke would come out of some part or other of so large an opening, so that the door can seldom be shut; and the cold air so nips the backs and heels of those that sit before the fire, that they have no comfort till either screens or settles are provided (at a considerable expence) to keep it off, which both cumber the room, and darken the fire-side. A moderate quantity of wood on the fire, in so large a hearth, seems but little; and, in so strong and cold a draught, warms but little; so that people are continually laying on more. In short, it is next to impossible to warm a room with such a fire-place: and I suppose our ancestors never thought of warming rooms to sit in; all they purposed was, to have a place to make a fire in, by which they might warm themselves when cold.

2. Most of these old-fashioned chimneys in towns and cities, have been, of late years, reduced to the second sort mentioned, by building jambs within them, narrowing the hearth, and making a low arch or breast. It is strange, methinks, that though chimneys have been so long in use, their construction should be so little understood till lately, that no workman pretended to make one which should always carry off all smoke, but a chimney-cloth was looked upon as essential to a chimney. This improvement, however, by small openings and low breasts, has been made in our days; and success in the first experiments has brought it into general use in cities, so that almost all new chimneys are now made of that sort, and much fewer bricks will make a stack of chimneys now than formerly. An improvement, so lately made, may give us room to believe, that still farther improvements may be found to remedy the inconveniencies yet remaining. For these new chimneys, though they keep rooms generally free from smoke, and, the opening being contracted, will allow the door to be shut, yet the funnel still requiring a considerable quantity of air, it rushes in at every crevice so strongly, as to make a continual whistling or howling; and it is very uncomfortable, as well as dangerous, to sit against any such crevice. Many colds are caught from this cause only, it being safer to sit in the open street, for then the pores do all close together, and the air does not strike so sharply against any particular part of the body.

The Spaniards have a proverbial saying,

If the wind blows on you through a hole,
Make your will, and take care of your soul.

Women particularly, from this cause, as they sit much in the house, get colds in the head, rheums and defluctions, which fall into their jaws and gums, and have destroyed early many a fine set of teeth in these northern colonies. Great and bright fires do also very much contribute to damage the eyes, dry and shrivel the skin, and bring on early the appearances of old age. In short, many of the diseases proceeding from colds, as fevers, pleurisies, &c. fatal to very great numbers of people, may be ascribed to strong drawing chimneys, whereby, in severe weather, a man is scorched before while he is froze behind.[45] In the mean time, very little is done by these chimneys towards warming the room; for the air round the fire-place, which is warmed by the direct rays from the fire, does not continue in the room, but is continually crouded and gathered into the chimney by the current of cold air coming behind it, and so is presently carried off.

In both these sorts of fire-places, the greatest part of the heat from the fire is lost; for as fire naturally darts heat every way, the back, the two jambs, and the hearth, drink up almost all that is given them, very little being reflected from bodies so dark, porous, and unpolished; and the upright heat, which is by far the greatest, flies directly up the chimney. Thus five-sixths at least of the heat (and consequently of the fuel) is wasted, and contributes nothing towards warming the room.

3. To remedy this, the Sieur Gauger gives, in his book entitled, La Mechanique de Feu, published in 1709, seven different constructions of the third sort of chimneys mentioned above, in which there are hollow cavities made by iron plates in the back, jambs, and hearths, through which plates the heat passing warms the air in those cavities, which is continually coming into the room fresh and warm. The invention was very ingenious, and had many conveniencies: the room was warmed in all parts, by the air flowing into it through the heated cavities: cold air was prevented rushing through the crevices, the funnel being sufficiently supplied by those cavities: much less fuel would serve, &c. But the first expence, which was very great, the intricacy of the design, and the difficulty of the execution, especially in old chimneys, discouraged the propagation of the invention; so that there are, I suppose, very few such chimneys now in use. [The upright heat, too, was almost all lost in these, as in the common chimneys.]