Imágenes de página

in the shell of an egg, and place its longest signed to write something on the small-pox diameter where the shortest now is, the shell shortly. We shall both be obliged to you for must break; but would be much harder to a word on this affair. break, if the whole internal substance were The chief particulars of our visitation, you . as solid and hard as the shell.

have in the public prints. But the less deMight not a wave, by any means raised in gree of mortality than usual in the common this supposed internal ocean of extremely way of infection, seems chiefly owing to the dense fluid, raise in some degree, as it passes, purging method designed to prevent the sethe present shell of incumbent earth, and break condary fever; a sixth, but had we been expeit in some places, as in earthquakes? And may rienced in this way, at the first method first not the progress of such wave, and the dis- begun and carried on in this town, and with orders it occasions among the solids of the success beyond expectation. We lost one in shell, account for the rumbling sound being eleven, one-coming of the distemper, probably first heard at a distance, augmenting as it ap- the proportion had been but one in thirteen or proaches, and gradually dying away as it pro- fourteen. In the year 1730 we lost one in ceeds? A circumstance observed by the in- nine, which is more favourable than ever behabitants of South America in their last great fore with us. The distemper pretty much earthquake, that noise coming from a place, the same then as now, but some circumsome degrees north of Lima, and being traced stances not so kind this time. by inquiry quite down to Buenos Ayres, pro If there be any particulars which you want ceeded regularly from north to south at the to know, please to signify what they are, and rate of leagues per minute, as I was in- I shall send them. formed by a very ingenious Peruvian whom I The number of our inhabitants decreases. met with at Paris. B. FRANKLIN. On a strict inquiry, the overseers of the poor

find but fourteen thousand one hundred and To M. Dubourg.

ninety whites, and one thousand five hundred

and forty-four blacks, including those absent On the Nature of Sea Coal.

on account of the small-pox, many of whom, it I Am persuaded, as well as you, that is probable, will never return. the sea coal has a vegetable origin, and that I pass this opportunity without any particuit has been formed near the surface of the lars of my old theme. One thing, however, I earth; but as preceding convulsions of nature must mention, which is, that perhaps my last had served to bring it very deep in many places, letters contained something that seemed to miand covered it with many different strata, we litate with your doctrine of the Origin, &c. are indebted to subsequent convulsions for But my design was only to relate the phenohaving brought within our view the extre- mena as they appeared to me. I have receivmities of its veins, so as to lead us to penetrate ed so much light and pleasure from your writthe earth in search of it. I visited last sum- ings, as to prejudice me in favour of every mer a large coal mine at Whitehaven, in Cum- thing from your hand, and leave me only liberland ; and in following the vein and de- berty to observe, and a power of dissenting scending by degrees towards the sea, I pene- when some great probability might oblige me: trated below the ocean, where the level of its and if at any time that be the case, you will surface was more than eight hundred fathom certainly hear of it. above my head, and the miners assured me, that their works extended some miles beyond the place where I then was, continually and

To Dr. Perkins. gradually descending under the sea. The slate, which forms the root of this coal mine,

Answer to the preceding. is impressed in many places with the figures of leaves and branches of fern, which undoubt

PHILADELPHIA, Aug. 13, 1752. edly grew at the surface when the slate was I RECEIVED your favour of the 3d instant. in the state of sand on the banks of the sea. Some time last winter I procured from one of Thus it appears that this vein of coal has suf- our physicians an account of the number of perfered a prodigious settlement.

sons inoculated during the five visitations of the B. FRANKLIN. 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, Dr. Perkins to Dr. Franklin.

the number exceeded eight hundred, and the Respecting the number of deaths in Philadelphia deaths were but four. I suppose Mr. V. will by Inoculation.

show you the account, if he ever received it. Boston, August 3, 1752. Those four were all that our doctors allow to SIR,—This comes to you on account of Dr. have died of the small-pox by inoculation, Douglass : he desired me to write to you for though I think there were two more of the what you know of the number that died of the inoculated who died of the distemper; but the inoculation in Philadelphia, telling me he de- eruptions appearing soon after the operation,

it is supposed they had taken the infection be- | still-heads and worms, and the physicians fore, in the common way.

were of opinion, that the mischief was occaI shall be glad to see what Dr. Douglass sioned by that use of lead. The legislature may write on the subject. I have a French of Massachusetts thereupon passed an act, piece printed at Paris, 1724, entitled, Obser- prohibiting, under severe penalties, the use of vations sur la Saignée du Pied, et sur la such still-heads and worms thereafter. Purgation au commencement de la Petite Ve In 1724, being in London, I went to work role, et Raisons de doubte contre l'Inocula- in the printing-house of Mr. Palmer, Bartho tion.- A letter of the doctor's is mentioned lomew-close, as a compositor. I there found a in it. If he or you have it not, and desire to practice, I had never seen before, of drying a see it, I will send it. Please to favour me case of types (which are wet in distribution) with the particulars of your purging method, by placing it sloping before the fire. I found to prevent the secondary fever.

this had the additional advantage, when the I am indebted for your preceding letter, types were not only dried but heated, of bebut business sometimes obliges me to postpone ing comfortable to the hands working over philosophical amusements. Whatever I have them in cold weather. I therefore sometimes wrote of that kind, are really, as they are en- heated my case when the types did not want titled, but Conjectures and Suppositions ; drying; But an old workman observing it, which ought always to give place, when care advised me not to do so, telling me I might ful observation militates against them. I own lose the use of my hands by it, as two of our I have too strong a penchant to the building companions had nearly done, one of whom, of hypotheses; they indulge my natural indo- that used to earn his guinea a week, could lence: I wish I had more of your patience not then make more than ten shillings, and and accuracy in making observations, on the other, who had the dangles, but seven which, alone, true philosophy can be founded. and sixpence. This, with a kind of obscure And, I assure you, nothing can be more oblig- pain, that I had sometimes felt, as it were, in ing to me, than your kind communication of the bones of my hand when working over those you make, however they may disagree the types made very hot, induced me to omit with my pre-conceived notions.

the practice. But talking afterwards with I am sorry to hear that the number of your Mr. James, a letter-founder in the same close, inhabitants decreases. I sometime since, and asking him if his people, who worked wrote a small paper of Thoughts on the peo- over the little furnaces of melted metal, were pling of Countries,* which, if I can find, I not subject to that disorder; he made light will send you, to obtain your sentiments. The of any danger from the effluvia, but ascribed favourable opinion you express of my writings it to particles of the metal swallowed with may, you see, occasion you more trouble than their food by slovenly workmen, who went to you expected from, B. FRANKLIN. their meals after handling the metal, without

well washing their fingers, so that some of

the metalline particles were taken off by To Benjamin Vaughan.

their bread and eaten with it. This appear

ed to have some reason in it. But the pain On the Effects of Lead upon the human Consti- I had experienced made me still afraid of those tution.*

effluvia. PHILADELPHIA, July 31, 1786.

Being in Derbyshire at some of the fur. I RECOLLECT that when I had last the plea- naces for smelting of lead ore, I was told, sure of seeing you at Southampton, now a that the smoke of those furnaces was pernitwelvemonth since, we had some conversation cious to the neighbouring grass and other ve on the bad effects of lead taken inwardly; getables; but I do not recollect to have heard and that at your request I promised to send any thing of the effect of such vegetables eat you in writing a particular account of several en by animals. It may be well to make the facts I then mentioned to you, of which you inquiry. thought some good use might be made. I In America I have often observed, that on now sit down to fulfil that promise.

the roofs of our shingled-houses, where moss is The first thing I remember of this kind was apt to grow in northern exposures, if there a general discourse in Boston when I was a be anything on the roof painted with white boy, of a complaint from North Carolina lead, such as balusters, or frames of doragainst New England rum, that it poisoned mant windows, &c. there is constantly a their people, giving them the dry belly-ache, streak on the shingles from such paint down with a loss of the use of their limbs. The dis- to the eaves, on which no moss will grow, tilleries being examined on the occasion, it but the wood remains constantly clean and was found, that several of them used leaden free from it. We seldom drink rain water

that fall on our houses; and if we did, per* This letter was publihed in a work by Dr. John haps the small quantity of lead descending Hunter, entitled Observations on the Discases of the Army.

from such paint might not be sufficient to pro


duce any sensible ill-effect on our bodies. But accustomed to see all the animals, with which I have been told of a case in Europe, I forget we are acquainted, eat and drink, it appears the place, where a whole family was afflicted to us difficult to conceive, how a toad can be with what we call the dry beily-ache, or coli- supported in such a dungeon: but if we reca pictorum, by drinking rain water. It was flect, that the necessity of nourishment, at a country-seat, which, being situated too which animals experience in their ordinary high to have the advantage of a well, was sup- state, proceeds from the continual waste of plied with water from a tank, which received their substance by perspiration, it will apthe water from the leaded roofs. This had pear less incredible, that some animals in a been drank several years without mischief, torpid state, perspiring less because they use but some young trees planted near the house no exercise, should have less need of aliment; growing up above the roof, and shedding their and that others, which are covered with leaves upon it, it was supposed, that an acid scales or shells, which stop perspiration, such in those leaves had corroded the lead they co as land and sea-turtles, serpents, and some vered, and furnished the water that year with species of fish, should be able to subsist a conits baneful particles and qualities.

siderable time without any nourishment whatWhen I was in Paris with sir John Pringle ever.-A plant, with its flowers, fades and in 1767, he visited La Charité, an hospital. dies immediately, if exposed to the air withparticularly famous for the cure of that mala- out having its root immersed in a humid soil, dy, and brought from thence a pamphlet, con- from which it may draw a sufficient quantity taining a list of the names of persons, speci- of moisture to supply that which exhales fying their professions or trades, who had from its substance and is carried off contibeen cured there. I had the curiosity to exa- nually by the air. Perhaps, however, if it mine that list, and found, that all the patients were buried in quicksilver, it might preserve were of trades, that some way or other use or for a considerable space of time its vegetable work in lead; such as plumbers, glaziers, life, its smell, and colour. If this be the painters, &c. excepting only two kinds, stone- case, it might prove a commodious method of cutters, and soldiers. In them, I could not transporting from distant countries those dereconcile it to my notion, that lead was the licate plants, which are unable to sustain the cause of that disorder. But on my mention- inclemency of the weather at sea, and which ing it to a physician of that hospital, he in- require particular care and attention. I have formed me, that the stone-cutters are conti- seen an instance of common flies preserved in nually using melted lead to fix the ends of a manner somewhat similar. They had been iron balustrades in stone; and that the sol- drowned in Madeira wine, apparently about diers had been employed by painters as labour- the time when it was bottled in Virginia, to ers in grinding of colours.

be sent hither (to London). At the opening This, my dear friend, is all I can at present of one of the bottles, at the house of a friend recollect on the subject. You will see by it, where I then was, three drowned flies fell that the opinion of this mischievous effect into the first glass that was filled. Having from lead, is at least above sixty years old; heard it remarked, that drowned flies were and you will observe with concern how long capable of being revived by the rays of the a useful truth may be known and exist, be sun, I proposed making the experiment upon fore it is generally received and practised on. these: they were therefore exposed to the

B. FRANKLIN. 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 To M. Dubourg.

recover life. They commenced by some con

vulsive motions of the thighs, and at length Observations on the prevailing Doctrines of Life they raised themselves upon their legs, wiped and Death.

their eyes with their fore-feet, beat and brush-YOUR observations on the causes of ed their wings with their hind-feet, and soon death, and the experiments which you pro- after began to fly, finding themselves in Old pose for recalling to life those who appear to England, without knowing how they came be killed by lightning, demonstrate equally thither. The third continued lifeless till sunyour sagacity and your humanity. It appears, set, when, losing all hopes of him, he was that the doctrines of life and death, in


thrown away. ral, are yet but little understood.

I wish it were possible, from this instance, A toad buried in sand will live, it is said, to invent a method of embalming drowned till the sand becomes petrified: and then, persons, in such a manner that they may be being enclosed in the stone, it may still live recalled to life at any period, however disfor we know not how many ages. The facts tant; for having a very ardent desire to see which are cited in support of this opinion are and observe the state of America an hundred too numerous, and too circumstantial, not to years hence, I should prefer to any ordinary leserve a certain degree of credit. As we are death, the being immersed in a cask of Ma



deira wine, with a few friends till that time, | This may be shown by several very easy exto be then recalled to life by the solar warmth periments. Take any elear glass bottle (a of my dear country! But since in all probabili- Florence flask stript of the straw is best) ty we live in an age too early and too near the place it before the fire, and as the air within infancy of science, to hope to see such an art is warmed and rarefied part of it will be driven brought in our time to its perfection, I must out of the bottle ; turn it up, place its mouth for the present content myself with the treat, in a vessel of water, and remove it from the which you are so kind as to promise me, of fire; then, as the air within cools and conthe resurrection of a fowl or a turkey-cock. tracts, you will see the water rise in the neck

B. FRANKLIN. 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 An account of the new-invented Pennsylva- and force out the water.-Or, fill a bladder

air within feels the heat, it will again distend nian Fire-Places : wherein their construc- not quite full of air, tie the neck tight, and tion and manner of operation is particularly lay it before a fire as near as may be without explained; their advantages above every scorching the bladder ; as the air within heats, other method of warming rooms demonstrated ; and all objections that have been der, till it becomes tight, as if full blown: re

you will perceive it to swell and fill the blad raised against the use of them answered move it to a cool place, and you will see it and obviated. With directions for putting fall gradually, till it becomes as lank as at them up, and for using them to the best first. advantage. And a Copper-Plate, in which

2. Air rarefied and distended by heat is the several parts of the machine are exactly fically* lighter than it was before, and will rise laid down, from a scale of equal parts.- in otħer air of greater density. As wood, oil, First printed at Philadelphia in 1745.

or any other matter specifically lighter than In these northern colonies the inhabitants water, if placed at the bottom of a vessel of keep fires to sit by generally seven months water, will rise till it comes to the top; so in the year ; that is, from the beginning of rarefied air will rise in common air, till it October, to the end of April; and, in some either comes to air of equal weight, or is by winters, near eight months, by taking in part cold reduced to its former density. of September and May.

A fire then being made in any chimney, Wood, our common fuel, which within the air over the fire is rarefied by the heat, these hundred years might be had at every becomes lighter, and therefore immediately man's door, must now be fetched near one rises in the funnel, and goes out; the other hundred miles to some towns, and makes a air in the room (filowing towards the chimney) very considerable article in the expense of supplies its place, is rarefied in its turn, and families.

rises likewise; the place of the air thus carAs therefore so much of the comfort' and ried out of the room, is supplied by fresh air conveniency of our lives, for so great a part coming in through doors and windows, or, if of the year, depends on the article of fire; they be shut, through every crevice with vio since fuel is become so expensive, and (as the lence, as may be seen by holding a candle to country is more cleared and settled) will of a key-hole: if the room be so tight as that course grow scarcer and dearer, any new pro- all the crevices together will not supply so posal for saving the wood, and for lessening much air as is continually carried off, then, the charge, and augmenting the benefit of in a little time, the current up the funnel fire, by some particular method of making and must flag, and the smoke being no longer managing it, may, at least be thought worth driven up, must come into the room. consideration.

1. Fire (i. e. common fire) throws out light, The new fire-places are a late invention to heat, and smoke (or fume.) The two first that purpose, of which this paper is intended move in right lines, and with great swiftness, to give a particular account.

the latter is but just separated from the fuel, That the reader may the better judge whe- and then moves only as it is carried by the ther this method of managing fire has any ad- stream of rarefied air: and without a contivantage over those heretofore in use, it may nual accession and recession of air, to carry off be proper to consider both the old and new the smoky fumes, they would remain crowded methods separately and particularly, and after- about the fire, and stifle it. wards make the comparison.

2. Heat may be separated from the smoke In order to this, it is necessary to under- as well as from the light, by means of a plate stand well, some few of the properties of air of iron, which will suffer heat to pass through and fire, viz.

it without the others. 1. Air is rarefied by heat, and condensed by cold, i. e. the same quantity of air takes

* Body or matter of any sort, is said to be specifically

heavier or lighter than other matter, when it has more up more space when warm than when cold. ! or less substance or weight in the same dimensions.


3. Fire sends out its rays of heat as well | little understood till lately, that no workman as rays of light equally every way; but the pretended to make one which should always greatest sensible heat is over the fire, where carry off all smoke, but a chimney-cloth was there is, besides the rays of heat shot upwards, looked upon as essential to a chimney. This a continual rising stream of hot air, heated by improvement, however, by small openings the rays shot round on every side.

and low breasts, has been made in our days; These things being understood, we proceed and success in the first experiments has to consider the fire-places heretofore in use, brought it into general use in cities, so that viz.

almost all new chimneys are now made of 1. The large open fire-places used in the that sort, and much fewer bricks will make a days of our fathers, and still generally in the stack of chimneys now than formerly. An country, and in kitchens,

improvement, so lately made, may give us 2. The newer-fashioned fire-places, with room to believe, that still farther improvelow breasts, and narrow hearths.

ments may be found to remedy the inconve3. Fire-places with hollow backs, hearths, niences yet remaining, For these new chimand jambs of iron (described by M. Gauger, neys, though they keep rooms generally free in his tract entitled, La Mechanique de from smoke, and the opening being contractFeu) for warming the air as it comes into the ed ; will allow the door to be shut, yet the fun

nel still requiring a considerable quantity of 4. The Holland stoves, with iron doors open- air, it rushes in at every crevice so strongly, ing into the room.

as to make a continual whistling or howling ; 5. The German stoves, which have no open- and it is very uncomfortable, as well as daning in the room where they are used, but the gerous, to sit against any such crevice. Many fire is put in from some other room, or from colds are caught from this cause only, it be without.

ing safer to sit in the open street, for then the 6. Iron pots, with open charcoal fires, placed pores do all close together and the air does in the middle of a room.

not strike so sharply against any particular part 1. The first of these methods has generally of the body. the conveniency of two warm seats, one in The Spaniards have a proverbial saying, each corner; but they are sometimes too hot to abide in, and, at other times, incommoded

If the wind blows on you through a hole, with the smoke; there is likewise good room

Make your will, and take care of your soul. for the cook to move, to hang on pots, &c. Women particularly from this cause, as they Their inconveniences are, that they almost always smoke, if the door be not left open; rheums and defluctions, which fall into their

sit much in the house, get colds in the head, that they require a large funnel, and a large jaws and gums, and have destroyed early many funnel carries off a great quantity of air, which occasions what is called a strong draf' a fine set of teeth in these northern colonies. to the chimney, without which strong draft tribute to damage the eyes, dry and shrivel the

Great and bright fires do also very much conthe smoke would come out of some part or other of so large an opening, so that the door skin, and bring on early the appearances of

old can seldom be shut; and the cold air so nips

age. In short, many of the diseases prothe backs and heels of those that sit before ceeding from colds, as fevers, pleurisies, &c. the fire, that they have no comfort till either ascribed to strong drawing chimneys, where

fatal to very great numbers of people, may be screens or settles are provided (at a considerable expense) to keep it off, which both cum- fore while he is froze behind.* In the mean

by, in severe weather, a man is scorched beber the room, and darken the fire-side. A moderate quantity of wood on the fire, in so

* As the writer is neither physician nor philosopher, large a hearth, seems but little; and, in so the reader may expect he should justify these his opistrong and cold a draught, warms but little; nions by the authority of some that are so. M. Clare

F. R. s. in his treatise of The motion of Fluids, says so that people are continually laying on more. page 246, &c. “ And here it may be remarked, that it In short, it is next to impossible to warm a is more prejudicial to health to sit near a window or a room with such a fire-place: and I suppose fire, than in a room without; for the consumption of

door, in a room where there are many candles and a our ancestors never thought of warming rooms air thereby occasioned, will always be very considerable, in; all they purposed was, to have a

and this must necessarily be replaced by cold air from

Down the chimney none place to make a fire in, by which they might stream of warm air always arising therein absolutely warm themselves when cold.

forbids it, the supply must therefore come in wherever 2. Most of these old-fashioned chimneys in small, let those who sit near them beware ; the smaller

other openings shall be found. If these happen to be towns and cities, have been, of late years, re- the floodgate, the smarter will be the stream. Was a duced to the second sort mentioned, by build- man, even in a sweat, to leap into a cold bath, or jump ing jambs within them, narrowing the hearth, frost, provided he do not continue over long therein, and and making a low arch or breast. It is strange, be in health when he does this, we see by experience methinks, that though chimneys have been so a window, into which a successive current of cold air long in use, their construction should be so comes, his pores are closed, and he gets a fever. In the

VOL. II.... 3 D


can enter, the

« AnteriorContinuar »