pears to be absolutely electrical, by forming its circuit through the same conductors with electricity, for instance, metals and water; and by being intercepted by the same non-conductors, for instance, glass and sealing-wax. I will not at present trouble you with a detail of our experiments, especially as we are daily advancing in them, but only observe, that, having discovered the back and breast of the animal (I speak in particular of that assemblage of pliant cylinders described by Lorenzini, running perpendicularly from the skin of the back to that of the breast,) to be in different states of electricity, we have been able to convey his shocks, though they were very small, through a circuit of four persons all feeling them; likewise through a considerable length of wire held by two insulated persons, one touching his lower surface and the other his

upper.

When the wire was exchanged for glass or sealingwax, no effect could be perceived. When resumed, the two persons were again sensible of the shock. These experiments have been varied and repeated times without number, by which the choice of conductors is beyond a doubt determined to be the same in the Torpedo as in the Leyden phial. The sensations they occasion, likewise, in the human frame are precisely similar. There is not an engourdissement or fourmillement of the Torpedo, that we do not exactly imitate with the phial by means of Mr. Lane's elec

trometer.

We have not yet perceived any spark or noise to

Franklin, as to the mode of conducting his experiments. (See Vol. V. pp. 412, 413.) Mr. Walsh's discoveries were deemed of sufficient importance to give him a claim to the Copley Medal, which was conferred on him by the Royal Society, November 30th, 1774. See SIR JOHN PRINGLE'S Six Discourses, p. 45.- EDITOR.

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accompany the shock, nor the pith balls to be ever affected. Indeed all our trials have been on very feeble subjects, whose shock was seldom sensible beyond the touching finger. I remember but one in at least two hundred, that I myself must have taken, to have extended above the elbow. Perhaps L'Isle de Ré, which we are about to visit, may furnish us with Torpedos, fresher taken and of more vigor, by which a farther insight into these matters may be obtained. Our experiments have been chiefly in the air, where the animal was more open to our examination than in water. It is a singularity, that the Torpedo when insulated should be able to give us, insulated likewise, thirty, forty, or fifty successive shocks from nearly the same part, and these with very little diminution in their strength; and indeed they were all minute. Each effort to give a shock is conveniently accompanied with a suppression of his eyes, by which even his attempts to give it to non-conductors could be ascertained. The animal, with respect to the rest of his body, is in a great degree motionless, but not wholly so.

You will please to acquaint Dr. Bancroft of our having verified his prediction concerning the Torpedo, and make any other communications of this matter you may judge proper. Here, I shall be glad to excite as far as I am able both electricians and naturalists to push their inquiries concerning this extraordinary animal, while the summer affords them the opportunity.

I am, with the truest sentiments of esteem and regard, dear Sir, &c. JOHN WALSH.

FROM JOHN BAPTIST TODERINI TO B. FRANKLIN.

Giving an Account of a Work published by him, entitled "Filosofia Frankliniana."

TRANSLATION.

Forli, 15 August, 1772.

SIR,

In submitting to you my little work, entitled Filosofia Frankliniana sopra le Punte Preservatrici del Fulmine, &c., I place it in the hands of a philosopher, known to the public as one of the most distinguished, whose happy inventions have so greatly advanced the progress of Natural Philosophy. Your great mind, truly English, and your enlightened views, have been directed to the subject of protecting houses and other edifices from lightning.

Availing myself of your ideas, I have thought of extending these preservatives to vessels and to magazines of powder. I propose every thing as derived from you, and as such I acknowledge it. I am very desirous of knowing your opinion of this little work. I shall profit by your suggestions. It will give me great pleasure, Sir, if you have time, and will have the goodness to inform me whether in America, or in England, these defences against lightning have ever been used for vessels; or, whether you, Mr. Watson, or others have invented such preservatives. Pray excuse my inquisitiveness, and if you will favor me with an answer, you can leave it with Mr. Berlendis, Venetian Minister at London. I am, with great respect, Sir,

Your most obedient, &c.

JOHN BAPTIST TODERINI, of the Society of Jesus.

ANSWER TO M. DUBOURG'S QUERIES RESPECTING THE

ARMONICA.*

London, 8 December, 1772.

When the glasses are ranged on the horizontal spindle, or, to make use of your expression, enfilés, and each one is definitely fixed in its place, the whole of the largest glass appears, at the extremity to the left; the following one, nearly enclosed in the preceding one, shows only about an inch of its border, which advances so much further than the edge of the larger glass; and so, in succession, each glass exceeds the one containing it, leaving by this placement an uncovered border on which the fingers may be applied. The glasses do not touch one another, but they are so near as not to admit a finger to pass between them; so that the interior border is not susceptible of being rubbed.

The finger is to be applied flat on the borders of the largest glasses, and on the borders of the smaller; but in part on the borders, and in part on the edges, of the glasses of an intermediate size. Nothing but experience can instruct with respect to this manutation, (fingering,) because the different-sized glasses require to be touched differently, some nearer the edge, and others farther from it. A few hours' exercise will teach this. B. F.

* See a description of the Armonica above, pp. 245-250; and also plate X.

Some Directions for drawing out the Tones from the Glasses of the Armonica.

Before you sit down to play, the fingers should be well washed with soap and water, and the soap well rinsed off.

The glasses must be always kept perfectly clean from the least greasiness; therefore suffer nobody to touch them with unwashed hands; for even the common slight natural greasiness of the skin rubbed on them will prevent their sounding for a long time.

You must be provided with a bottle of rain water, (spring water is generally too hard and produces a harsh tone,) and a middling sponge in a little slopbowl, in which you must keep so much of the water' that the sponge may be always very wet.

In a teacup keep also ready some fine scraped chalk, free from grit, to be used on occasion.

The fingers when you begin to play should not only be wet on the surface, but the skin a little soaked, which is readily done by pressing them hard a few times in the sponge.

The first thing after setting the glasses in motion is to pass the sponge slowly along from the biggest glass to the smallest, suffering it to rest on each glass during at least one revolution of the glasses, whereby they will all be made moderately wet. If too much water is left on them, they will not sound so readily.

If the instrument is near a window, let the window be shut or the curtain drawn, as wind or sunshine on the glasses dries them too fast.

When these particulars are all attended to, and the directions observed, the tone comes forth finely with the slightest pressure of the fingers imaginable, and DD*

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