if it was not, the fancy of the hen must have operated through the shell to work the effect. I flatter myself, however, that, prone as we are to delight and believe in the marvellous, this is too marvellous and absurd a notion to gain much credit from a woman of your good sense. But, Madam, an anatomist will tell you, that, considering the nature of the communication betwixt the mother and the embryo, it seems equally incomprehensible to him, that an embryo should receive an impression from the fancy of the mother, through such a labyrinth of vessels, as that a chick should, through the pores of the egg-shell.

If after what I have here said upon the subject of the hen and the egg, you have still a secret persuasion, that the hen may (in some wonderful manner, you do not know how) whilst she is sitting, affect the chick in the egg, so as to alter its frame, know, for a certainty, that eggs hatched in dunghills, stoves, and ovens, produce as many monstrous births, as those which are hatched by hens; which, I should imagine, proves irrefragably, that the chick is produced in the very shape in which it was formed.

I hope, from the light in which I have placed this popular piece of superstition, you are now convinced it has not the least foundation in truth. It is not more than a century since some men of learning gave credit to the efficacy of sympathetic medicines; they believed that sympathetic medicines, like other charms, communicated their virtues to patients at a distance. Learning and good sense have at length utterly banished this visionary conceit; and I do not doubt but, in another century, the prejudice I have been here combating, will meet with the same contempt. Men of letters do even now embrace the doctrine I inculcate; and it is to be hoped, that in a short time, it will be the opinion of the common people.

1764, Oct.

I am, Madam, &c.

IV. Solution of Optical Phenomena. Part of a Letter from James Logan, of Philadelphia, to Sir Hans Sloane. From an original MS. communicated by Peter Collinson, Esq.

IT

may perhaps be needless now to add any thing in confirmation of Doctor Wallis's solution of the sun and moon appearing so much larger at rising and setting, than in a greater altitude; though some have gone on very absurdly, and still go on to account for it from vapours; which I remember was given me in my youth for the true cause of it.

It is true, indeed, that it is these vapours in the atmosphere alone, that make those bodies, when very near to the horizon, appear in a spheriodical form, by refracting, and thereby raising (to sight) the lower limb more than the upper, yet these can be no cause of the other. Sun or moon, each subtending about half a degree, appears in the meridian of the breadth of eight or ten inches, to some eyes more, and to others less, and in the horizon to be two or three feet, more or less, according to the extent of ground they are seen over.

But if one has an opportunity, as I have here frequently had, of seeing the sun rise or set over a small eminence at the distance of a mile or two, with tall trees standing on it pretty close, as is usual in woods, without underwood, his body will then appear to be ten or twelve feet in breadth, according to the distance and circumstances of the trees he is seen through; and where there has been some thin underwood, or a few saplings, I have observed that the sun setting red, has appeared through them like a large extensive flame, as if some house was on fire beyond them.

Now the reason of this is obvious, viz. that being well acquainted with trees, the ideas of the space they take up are in a manner fixed, and as one of those trees subtends an angle at the eye, perhaps not exceeding two or three seconds, and would scarcely be distinguishable, were it not for the strong light behind them, the sun's diameter of above thirty inches, takes in several of them, and therefore will naturally be judged vastly larger. Hence it is evident, that those bodies appear greater or less, according to the objects interposed, or taken in by the eye on viewing them, and to this only is this phenomenon to be imputed.

J. LOGAN.

Part of a second Letter from James Logan, to Sir Hans Sloane.

I OBSERVED the ingenious gentleman, Stephen Hales, in his Vegetable Statics, to mention that phenomenon of the streaks or darts of lightning in thunder storms appearing crooked and angular (I do not remember his words) as a thing unaccounted for, and therefore guessed at a solution of it; but if I mistake not, I sometime since discovered the true one, which was this-Having a sash window, glazed with bad or waved glass, and sitting about twelve feet distance from it, one of my people was carrying by that window, at some distance from it, a long lath on his shoulder, which, through that glass, appeared to my view exactly in the form D d

VOL. II.

that those streaks of lightning are seen, and as thunder i generally pictured in the hand of Jupiter. And any one with such wavey glass, may very easily make the like experiment.

Now it is evident that the clouds are generally distinct collections of vapours like fleeces, and therefore that the rays of light through them, must pass through very different densities, and accordingly suffer very great refractions, as great at least as could be caused by one thin plate of glass, which, notwithstanding, will very fully produce the same phenomenon. From thence, therefore, undoubtedly that appearance must arise; for it is most highly absurd to imagine that fire darted with such a rapidity, can from any assignable cause deviate in fact from a right line in the manner it appears to us; and this, if duly considered, may probably be found a plenary solution.

1767, Nov.

J. LOGAN

V. A surprising Accident which happened to a Woman at Cesena.

THIS woman was 62 years of age, and had been used to wash and rub herself every day with spirit of camphire, to prevent colds and coughs. On the 14th of March, 1731, in the evening, she went up to her room without any unusual symptom, only that she seemed somewhat melancholy. In the morning she was found near her bed burnt to ashes, all but her shin-bones and feet, and three fingers of one hand: the ashes were clammy, and stunk intolerably. The walls of the room, the bed and other furniture, were covered with a fine but moist dust, which had penetrated into the chamber above it. The cieling was almost covered with a sort of moisture of a dark yellow colour, which gave a very offensive smell. Those parts of the body that remained were of a blackish bue; nothing else in the room was consumed; only the tallow of two candles quite melted, but the wick not burnt: the blackish hue of the remains of the body, the consumption of the other parts, and their reduction to ashes, were evident proofs of a fire: yet common fire can hardly reduce so large a body to ashes; for it has often appeared, that in great conflagrations, the bodies have been dried, scorched, and somewhat burnt in the external parts, but not entirely consumed. It is likewise certain, that common fire would have taken hold of the bed, the chamber, and

even the whole house: besides, there was neither fire nor light in the chamber; and the serenity of the air left no room to suspect, that there was any lightning that could produce such an accident; because there was not the least hole found in the sides of the chamber. It is therefore not unreasonable to conclude, that this poor woman was consumed by a fire that kindled within her own body, proceeding from the oily particles of the spirits, excited by chafing and the heat of her constitution. These are the thoughts of Signior Maffei and Father Bellivaga, which are corroborated by the examples of powder magazines; for the exhalations from the powder, being put into a violent motion by some external cause, have sometimes blown up the magazine, without the help of any apparent fire. A human body hath likewise in it some oleous and saline particles, capable of producing a fire: we even find, that the sweat of some people smells like brimstone. Phosphoruses are made of urine, which partly kindle of themselves: therefore, if to these particles of the body, brandy and camphire be added, the two ingredients which compose the spirit of camphire, their particles, especially by the means of chafing, cannot but cause a violent motion in the particles of the blood and other juices, which will produce a vehement attrition or rubbing against each other. Such attrition is capable of producing fire even in cold bodies, as appears by the striking of a piece of steel upon a flint, and the rubbing of two sticks against each other: the sun draws every day from bodies, not the most combustible, vapours which produce fire, when pent up in a narrow compass. If we cause a quantity of camphire to evaporate in a close chamber till it is filled with the vapour, and then enter it with a lighted torch, the vapour takes fire at once, and causes a flash like that of lightning: besides all this, the fermentation of the juices in the woman's body, may have contributed something to the effect; for a flame is often produced by the mixture and fermentation of certain liquors. The reason why the shinbones and the feet were not burnt, may be this, that she did not chafe those parts with the spirits, or at least not so much as the other parts of the body; and possibly, she never used the three fingers, that remained unconsumed, in chafing. The oiliness of the ashes, it is likely, proceeded from the fat of the body. As the fire was kindled at once in the veins and most minute vessels of the body, we may conclude, that it consumed it in a moment; which sudden effects could not have been produced by other fires, that were not so inclosed in the body. Some effect of this

fire was found in the upper rooms, because such a sudden beat flies chiefly upward; which was likewise the cause that the floor of her chamber escaped being burnt, and that none of the furniture was touched; for a piece of paper may be drawn suddenly through the greatest flame without being set on fire.

1736, Nov.

VI. Account of Margaret Cutting, of Wickham Market, inSuffolk, who spoke readily and intelligibly, though she had lost her Tongue.

MR. BODDINGTON, Turkey merchant, at Ipswich, com municated this extraordinary fact to the Royal Society, July 1, 1742, who thought it worthy of an exact inquiry, which was made by Mr. Boddington, the Rev. Mr. Norcutt, and Mr. Hammond, a skilful anatomist, who attested the following circumstances.

April 9, 1742, We saw Margaret Cutting, who informed us she was about 24 years old; that when she was but 4 years of age a cancer appeared on the upper part of her tongue, which soon eat its way to the root. Mr. Scotchmore, surgeon, at Saxmundham, used the best means he could for her relief, but pronounced the case incurable. One day when he was injecting some medicine into her mouth, her tongue dropped out; the girl immediately saying, to their great surprise, Don't be frighted Mamma! 'twill grow again. In a quarter of a year afterwards she was quite cured. In examining her mouth we found not the least appearance of any tongue remaining, nor any uvula; but we observed a fleshy excrescence under the left jaw, extending itself almost to the place where the uvula should be, about a finger broad. This did not appear till some years after the cure; it is not moveable. The passage to the throat, where the uvula should be, is circular, and will admit a small nutmeg. She performed the swallowing of solids and liquids as well as we could; she discoursed as well as other persons do, but with a little tone through the nose. Letters and sylJables she pronounced very articulately, and vowels perfectly; as also those consonants that require most the help of the tongue, d, 1, t, r, n. She read to us in a book very distinctly, and sung very prettily. What is still more wonderful, notwithstanding her loss of this organ, she distinguishes all tastes very nicely. To this certificate may be added the attestation