You often entertain us with accounts of new discoveries. Permit me to communicate to the public, through your paper, one that has lately been made by myself, and which I conceive may be of great utility.

I was the other evening in a grand company, where the new lamp of Messrs. Quinquet and Lange was introduced, and much admired for its splendour; but a general inquiry was made, whether the oil it consumed was not in proportion to the light it afforded, in which case there would be no saving in the use of it. No one present could satisfy...

You inquired about my gout, and I forgot to acquaint you, that I had treated it a little cavalierly in its two last accesses. Finding one night that my foot gave me more pain after it was covered warm in bed, I put it out of bed naked; and, perceiving it easier, I let it remain longer than I at first designed, and at length fell asleep leaving it there till morning. The pain did not return, and I grew well. Next winter, having a second attack, I repeated the experiment; not with such immediate success in dismissing the gout,...

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...

In compliance with your request, I send you the following account of what I can at present recollect relating to the effects of electricity in paralytic cases, which have fallen under my observation.

Some years since, when the news-papers made mention of great cures performed in Italy and Germany, by means of electricity, a number of paralytics, were brought to me from different parts of Pensylvania, and the neighboring provinces, to be electrised, which I did for them at their request. My method was, to place the patient first in a chair, on an electric stool, and draw a number...

I recollect, that, when I had the great pleasure of seeing you at Southampton, now a 12month since, we had some conversation on the bad effects of lead taken inwardly; and that at your request I promis’d to send you in writing a particular account of several facts I then mention’d 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,...

Eat and drink such an exact quantity as the constitution of thy body allows of, in reference to the services of the mind.

They that study much, ought not to eat so much as those that work hard, their digestion being not so good.

The exact quantity and quality, being found out, is to be kept to constantly.

Excess in all other things whatever, as well as in meat and drink, is also to be avoided.

Youth, age, and sick, require a different quantity.

And so do those of contrary complexions; for that which is too much for a phlegmatick...

As a great part of our life is spent in sleep during which we have sometimes pleasant and sometimes painful dreams, it becomes of some consequence to obtain the one kind and avoid the other; for whether real or imaginary, pain is pain and pleasure is pleasure. If we can sleep without dreaming, it is well that painful dreams are avoided. If while we sleep we can have any pleasing dream, it is, as the French say, autant de gagné, so much added to the pleasure of life.

To this end it is, in the first place, necessary to be...

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...

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 L., 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 palettes, each about...

I have received your kind letter of May 10. You seem so sensible of your error in so hastily suspecting me, that I am now in my turn sorry I took notice of it. Let us then suppose that accompt ballanced and settled, and think no more of it.—

In some former letter I believe I mention’d the price of the books, which I have now forgotten: But I think it was 3 S each. — To be sure there are objections to the Doctrine of Pre-existence. But it seems to have been invented with a good intention, to save...

By Mr. Dollond’s saying, that my double spectacles can only serve particular eyes, I doubt he has not been rightly informed of their construction. I imagine it will be found pretty generally true, that the same convexity of glass, through which a man sees clearest and best at the distance proper for reading, is not the best for greater distances. I therefore had formerly two pair of spectacles, which I shifted occasionally, as in travelling I sometimes read, and often wanted to regard the prospects. Finding this change troublesome, and not always sufficiently ready, I had the glasses cut, and...

Experiments made in electricity first gave philosophers a suspicion that the matter of lightning was the same with the electric matter. Experiments afterwards made on lightning obtained from the clouds by pointed rods, received into bottles, and subjected to every trial, have since proved this suspicion to be perfectly well founded; and that whatever properties we find in electricity, are also the properties of lightning.

This matter of lightning, or of electricity, is an extream subtile fluid, penetrating other bodies, and subsisting in them, equally diffused.

When by any operation of art or nature, there happens to be a greater...

Pointed conductors to secure buildings from lightning have now been in use near 20 years in America, and are there become so common, that numbers of them appear on private houses in every street of the principal towns, besides those on churches, public buildings, magazines of powder, and gentlemen’s seats in the country. Thunder storms are much more frequent there than in Europe, and hitherto there has been no instance of a house so guarded being damaged by lightning; for wherever it has broke over any of them the point has always received it, & the conductor has convey’d it...

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 fewel, which within these 100 years might be had at every man’s door, must now be fetch’d near 100 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...

My answer to your questions concerning the mode of rendering meat tender by electricity, can only be founded upon conjecture; for I have not experiments enough to warrant the facts. All that I can say at present is, that I think electricity might be employed for this purpose, and I shall state what follows as the observations or reasons which make me presume so.

It has been observed that lightning, by rarefying and reducing into vapour the moisture contained in solid wood, in an oak, for instance, has forcibly separated its fibres, and broken it into small splinters; that, by...

I think I before acknowledg’d your favour of Feb 29. I have since received that of May 30. I am glad my canal papers were agreable to you. If any work of that kind is set on foot in America, I think it would be saving money to engage by a handsome salary an engineer from hence who has been accustomed to such business. The many canals on foot here under different great masters, are daily raising a number of pupils in the art, some of whom may want employ hereafter; and a single mistake thro’ inexperience, in such important...

It is remark’d in North America, that the English farmers, when they first arrive there, finding the soil and climate proper for the husbandry they have been accustomed to, and particularly suitable for raising wheat, they despise and neglect the culture of mayz: but observing the advantage it affords their neighbours, the older inhabitants, they by degrees get more and more into the practice of raising it; and the face of the country shows, from time to time, that the culture of that grain goes on visibly augmenting.

The inducements are, the many different ways in which it may be...

I once promised myself the pleasure of seeing you at Turin; but as that is not now likely to happen, being just about returning to my native country, America, I sit down to take leave of you (among others of my European friends that I cannot see) by writing.

I thank you for the honourable mention you have so frequently made of me in your letters to Mr. Collinson and others, for the generous defence you undertook and executed with so much success, of my electrical opinions; and for the valuable present you have made me of your new work,...

On Wednesday the 27th instant, the new aerostatic experiment, invented by Messrs. Mongolfier of Annonay was repeated by Mr. Charles; Professor of Experimental Philosophy at Paris.

A hollow globe 12 feet diameter was formed of what is called in England oiled silk, here Taffetas gommée, the silk being impregnated with a solution of gum-elastic in lintseed oil, as is said. The parts were sewed together while wet with the gum, and some of it was afterwards passed over the seams, to render it as tight as possible.

It was afterwards filled with the inflammable air that is produced by pouring...

The publick were promis’d a printed particular account of the rise & progress of the balloon invention, to be publish’d about the end of last month. I waited for it, to send it to you expecting it would be more satisfactory than any thing I could write; but it does not yet appear. We have only at present the enclos’d pamphlet which does not answer the expectation given us. I send you with it some prints. That of the balloon rais’d at Versailles is said to be an exact representation. I was not present, but am told it was fill’d...

I received your friendly letter of the 7^th inst. I am glad my letters respecting the aerostatic experiment were not unacceptable. But as more perfect accounts of the construction and management of that machine have been and will be publish’d before your transactions, and from which extracts may be made that will be more particular & therefore more satisfactory, I think it best not to print those letters. I say this in answer to your question for I did not indeed write them with a view of their being inserted. M. Faujas de St. Fond acquainted me yesterday, that a...

In mine of yesterday I promised to give you an account of Messrs. Charles & Robert’s experiment, which was to have been made this day, and at which I intended to be present. Being a little indisposed, and the air cool, and the ground damp, I declined going into the garden of the Tuileries, where the balloon was placed, not knowing how long I might be obliged to wait there before it was ready to depart, and chose to stay in my carriage near the statue of Louis XV., from whence I could well see it rise, and have an...

I have this day received your favor of the 2d inst. Every information in my power, respecting the balloons, I sent you just before Christmas, contained in copies of my letters to Sir Joseph Banks. There is no secret in the affair, and I make no doubt that a person coming from you would easily obtain a sight of the different balloons of Montgolfier and Charles, with all the instructions wanted; and, if you undertake to make one, I think it extremely proper and necessary to send an ingenious man here for that purpose: otherwise, for want of attention to...

Acording to your request, I now send you the Arithmetical Curiosity, of which this is the history.

Being one day in the country, at the house of our common friend, the late learned, Mr. Logan, he shewed me a folio French book, filled with magic squares, . . . in which he said, the author had discovered great ingenuity and dexterity in the management of numbers; and, though several other foreigners had distinguished themselves in the same way, he did not recollect that any one Englishman had done anything of the kind remarkable.

. . . I then confessed to...

Chagrined a little that we have been hitherto able to produce nothing in this way of use to mankind; and the hot weather coming on, when electrical experiments are not so agreeable, it is proposed to put an end to them for this season, somewhat humorously, in a party of pleasure on the banks of Skuylkil. Spirits, at the same time, are to be fired by a spark sent from side to side through the river, without any other conductor than the water; an experiment which we some time since performed, to the amazement of many.

A turkey is to...

Your question, how I came first to think of proposing the experiment of drawing down the lightning, in order to ascertain its sameness with the electric fluid, I cannot answer better than by giving you an extract from the minutes I used to keep of the experiments I made, with memorandums of such as I purposed to make, the reasons for making them, and the observations that arose upon them, from which minutes my letters were afterwards drawn. By this extract you will see, that the thought was not so much “an out-of-the-way one,” but that it might have occurred...

As frequent mention is made in public papers from Europe of the success of the Philadelphia experiment for drawing the electric fire from clouds by means of pointed rods of iron erected on high buildings, &, it may be agreeable to the curious to be informed, that the same experiment has succeeded in Philadelphia, though made in a different and more easy manner, which is as follows:

Make a small cross of two light strips of cedar, the arms so long as to reach to the four corners of a large thin silk handkerchief when extended; tie the corners of...

On Sunday last about 45 minutes after 3 in the morning a dwelling house, one of a continued row on the west side of Second street in this town, was struck by lightning, but, being at that time untenanted, no person was hurt. About 6 o’clock the same morning, I went to take a view thereof, and at that time made some notes of the course which I observed the lightning to have taken in its passage, and also of some of its effects on the house, when they appeared to me not unworthy of notice.

The course is as...

I have received your very obliging and very ingenious letter by Captain Kearney. Your observations upon the electricity of fogs and the air in Ireland, and upon different circumstances of storms, appear to me very curious, and I thank you for them. There is not, in my opinion, any part of the earth whatever which is, or can be, naturally in a state of negative electricity; and, though different circumstances may occasion an inequality in the distribution of the fluid, the equilibrium is immediately restored by means of its extreme subtilty, and of the excellent conductors with which the humid...

Give me leave on this occasion to extend a little the sense of your position, that “Melody and Harmony are separately agreeable, and in union delightful,” and to give it as my opinion, that the reason why the Scotch tunes have lived so long, and will probably live for ever (if they escape being stifled in modern affected ornament), is merely this, that they are really compositions of melody and harmony united, or rather that their melody is harmony. I mean the simple tunes sung by a single voice. As this will appear paradoxical, I must explain my meaning. In...

Vessels are sometimes retarded, and sometimes forwarded in their voyages, by currents at sea, which are often not perceived. About the year 1769 or 70, there was an application made by the Board of Customs at Boston, to the Lords of the Treasury in London, complaining that the packets between Falmouth and New York were generally a fortnight longer in their passages, than merchant ships from London to Rhode Island, and proposing that for the future they should be ordered to Rhode Island instead of New York. Being then concerned in the management of the American post-office, I happened to...

Discoursing with Captain Folger, a very intelligent mariner of the Island of Nantucket, in New England, concerning the long passages made by some ships bound from England to New York, I received from him the following information, viz.,

That the island in which he lives is inhabited chiefly by people concerned in the whale fishery, in which they employed near 150 sail of vessels; that the whales are found generally near the edges of the Gulph Stream, a strong current so called, which comes out of the Gulph of Florida, passing northeasterly along the coast of America, and then turning...

You may remember, that when we were travelling together in Holland, you remarked, that the trackschuyt in one of the stages went slower than usual, and inquired of the boatman, what might be the reason; who answered, that it had been a dry season, and the water in the canal was low. On being again asked if it was so low as that the boat touched the muddy bottom; he said, no, not so low as that, but so low as to make it harder for the horse to draw the boat. We neither of us at first could conceive...

In yours of May 19, which I have before me, you speak of the ease with which salt water may be made fresh by distillation, supposing it to be, as I had said, that in evaporation the air would take up water, but not the salt that was mix’d with it. It is true, that distill’d sea water will not be salt, but there are other disagreable qualities that rise with the water in distillation; which indeed several besides Dr. Hales have endeavoured by sundry means to prevent; but as yet their methods have not been brought much into use....

During our passage to Madeira, the weather being warm, and the cabbin windows constantly open for the benefit of the air, the candles at night flared and run very much, which was an inconvenience. At Madeira we got oil to burn, and with a common glass tumbler or beaker, slung in wire, and suspended to the cieling of the cabbin, and a little wire hoop for the wick, furnish’d with corks to float on the oil, I made an Italian lamp, that gave us very good light all over the table. That glass at bottom contained water to about one...

In compliance with your request, I have endeavoured to recollect the circumstances of the American experiments I formerly mentioned to you, of raising a flame on the surface of some waters there.

When I passed through New Jersey in 1764, I heard it several times mentioned, that, by applying a lighted candle near the surface of some of their rivers, a sudden flame would catch and spread on the water, continuing to burn for near half a minute. But the accounts I received were so imperfect, that I could form no guess at the cause of such an effect, and...

We have had the smallpox here lately, which raged violently while it lasted. There have been about fifty persons inoculated, who all recovered except a child of the doctor’s upon whom the smallpox appeared within a day or two after the operation, and who is therefore thought to have been certainly infected before. In one family in my neighbourhood there appeared a great mortality. Mr. George Claypoole . . . had, by industry, acquired a great estate, and being in excellent business, a merchant, would probably have doubled it, had he lived according to the common course of years. He...

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 enclosed 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...

I shall communicate your judicious remark, relating to the septic quality of the air transpired by patients in putrid diseases, to my friend Dr. Priestley. I hope that after having discovered the benefit of fresh and cool air applied to the sick, people will begin to suspect that possibly it may do no harm to the well. I have not seen Dr. Cullen’s book, but am glad to hear that he speaks of catarrhs or colds by contagion. I have long been satisfied from observation, that besides the general colds now termed influenzas, (which may possibly spread by contagion, as...

It is a siziness and thickness of the blood, whereby the smaller vessels are obstructed, and the perspirable matter retained, which being retained offends both by its quantity and quality; by quantity, as it overfills the vessels, and by its quality, as part of it is acrid, and being retained, produces coughs and sneezing by irritation....

Professor simson, of Glasgow, lately communicated to me some curious experiments of a physician of his acquaintance, by which it appeared that an extraordinary degree of cold, even to freezing, might be produced by evaporation. I have not had leisure to repeat and examine more than the first and easiest of them, viz. Wet the ball of a thermometer by a feather dipped in spirit of wine, which has been kept in the same room, and has, of course, the same degree of heat or cold. The mercury sinks presently three or four degrees, and the quicker, if, during the...

In a former letter I mentioned the experiment for cooling bodies by evaporation, and that I had, by repeatedly wetting the thermometer with common spirits, brought the mercury down five or six degrees. Being lately at Cambridge, and mentioning this in conversation with Dr. Hadley, professor of chemistry there, he proposed repeating the experiments with ether, instead of common spirits, as the ether is much quicker in evaporation. We accordingly went to his chamber, where he had both ether and a thermometer. By dipping first the ball of the thermometer into the ether, it appeared that the ether was precisely...

I thank you for the curious facts you have communicated to me relating to springs. I think with you, that most springs arise from rains, dews, or ponds, on higher grounds; yet possibly some, that break out near the tops of high hollow mountains, may proceed from the abyss, or from water in the caverns of the earth, rarefied by its internal heat, and raised in vapour, till the cold region near the tops of such mountains condenses the vapour into water again, which comes forth in springs, and runs down on the outside of the mountains, as it ascended...

I have your agreable letter from Bristol, which I take this first leisure hour to answer, having for some time been much engag’d in business.

Your first question, What is the reason the water at this place, tho’ cold at the spring, becomes warm by pumping? it will be most prudent in me to forbear attempting to answer, till, by a more circumstantial account, you assure me of the fact. I own I should expect that operation to warm, not so much the water pump’d, as the person pumping. The rubbing of dry solids together has been long observ’d to...

It is, as you observed in our late conversation, a very general opinion, that all rivers run into the sea, or deposit their waters there. ‘Tis a kind of audacity to call such general opinions in question, and may subject one to censure. But we must hazard something in what we think the cause of truth: and if we propose our objections modestly we shall tho’ mistaken, deserve a censure less severe, than when we are both mistaken and insolent.

That some rivers run into the sea is beyond a doubt; such for instance, are the Amazones and, I think,...

It has, indeed, as you observe, been the opinion of some very great naturalists, that the sea is salt only from the dissolution of mineral or rock salt, which its waters happened to meet with. But this opinion takes it for granted that all water was originally fresh, of which we can have no proof. I own I am inclined to a different opinion, and rather think all the water on this globe was originally salt, and that the fresh water we find in springs and rivers, is the produce of distillation. The sun raises the vapours from the sea,...

Agreeable to your request, I send you my reasons for thinking that our northeast storms in North America begin first, in point of time, in the south west parts: That is to say, the air in Georgia, the farthest of our colonies to the Southwest, begins to move southwesterly before the air of Carolina, which is the next colony northeastward; the air of Carolina has the same motion before the air of Virginia, which lies still more northeastward; and so on northeasterly through Pennsylvania, New-York, New-England, &c., quite to Newfoundland.

These northeast storms are generally very violent, continue sometimes two...

I thank you for the remarks of your learned friend at Carlisle. I had, when a youth, read and smiled at Pliny’s account of a practice among the seamen of his time, to still the waves in a storm by pouring oil into the sea; which he mentions, as well as the use made of oil by the diver; but the stilling a tempest by throwing vinegar into the air had escaped me. I think with your friend, that it has been of late too much the mode to slight the learning of the ancients. The learned, too, are apt...

I agree with you, that by means of a vacuum in a whirlwind, water cannot be suppos’d to rise in large masses to the region of the clouds: for the pressure of the surrounding atmosphere could not force it up in a continu’d body or column, to a much greater height than thirty feet. But if there really is a vacuum in the center, or near the axis of whirlwinds, then I think water may rise in such vacuum to that height, or to less height, as the vacuum may be less perfect.

I had not read Stuart’s Acc^t. in...

A considerable time after its arrival, I received the box of seeds you sent me the beginning of last year, with your observations on spots of the sun. The seeds I distributed among some of my friends who are curious; accept my thankful acknowledgments for them. The observations I communicated to our astronomers of the Royal Society, who are much pleased with them, and hand them about from one to another; so that I have had little opportunity of examining them myself, they not being yet returned to me.

Here are various opinions about the solar spots. Some think them...

In considering your fav^r of the 16th past, I recollected my having wrote you answers to some queries concerning the difference between El per se, and Non-Els, and the effects of air in El. experiments, which, I apprehend, you may not have received. The date I have forgot.

We have been us’d to call those bodies Els per se, which would not conduct the electric fluid; we once imagin’d that only such bodies contain’d that fluid; afterwards that they contain’d none of it, [and only educed it from other bodies;] but farther experiments shew’d our mistakes. It is to be...

If the electrical fluid is truly accumulated on the inside of a Leyden phial, and expelled in the same proportion from the other side, why are the particles of glass not all thrown outwards, when the phial being overcharged breaks, or is perforated by a spontaneous explosion?

By the circumstances that have appeared to me, in all the jarrs that I have seen perforated at the time of their explosion, I have imagined that the charge did not pass by those perforations. Several single jarrs, that have broke while I was charging them, have shown, besides the perforation in the...

Our ancient correspondence used to have something philosophical in it. As you are now more free from public cares, and I expect to be so in a few months, why may we not resume that kind of correspondence? Our much regretted friend Winthrop once made me the compliment, that I was good at starting game for philosophers; let me try if I can start a little for you.

Has the question, how came the earth by its magnetism, ever been consider’d?

Is it likely that iron ore immediately existed when this globe was first form’d; or may it not rather...

Your explication of the crooked direction of lightning appears to me both ingenious and solid. When we can account as satisfactorily for the electrification of clouds, I think that branch of natural philosophy will be nearly compleat.

The air, undoubtedly, obstructs the motion of the electric fluid. Dry air prevents the dissipation of an electric atmosphere, the denser the more, as in cold weather. I question whether such an atmosphere can be retained by a body in vacuo. A common electrical vial requires a non-electric communication from the wire to every part of the charged glass; otherwise, being dry and...

I have perused your paper on sound, and would freely mention to you, as you desire it, every thing that appeared to me to need correction: but nothing of that kind occurs to me, unless it be, where you speak of the air as “the best medium for conveying sound.” Perhaps this is speaking rather too positively, if there be, as I think there are, some other mediums that will convey it farther and more readily. It is a well-known experiment, that the scratching of a pin at one end of a long piece of timber, may be heard by...

I sent you sometime since, directed to the care of M. Molini, a bookseller near the Quay des Augustins a tooth that I mention’d to you when I had the pleasure of meeting with you at the Marquis de Courtanvaux’s. It was found near the River Ohio in America, about 200 leagues below Fort du Quesne, at what is called the Great Licking Place, where the earth has a saltish taste that is agreable to the buffaloes & deer, who come there at certain seasons in great numbers to lick the same. At this place have been found the skeletons...

At Passy, near Paris, April 6, 1782, being with M. de Chaumont, viewing his quarry, he mention’d to me, that the workmen had found a living toad shut up in the stone. On questioning one of them, he told us, they had found four in different cells which had no communication; that they were very lively and active when set at liberty; that there was in each cell some loose, soft, yellowish earth, which appeared to be very moist. We asked, if he could show us the parts of the stone that form’d the cells. He said, No; for they...