In order to render the instrument still more portable we may employ a piece of tape as a measure, fixing to one end of it a double piece of card with an aperture, and with some pins projecting from its edge for holding the wool either between its folds or on the pins, and to the other end a small weight, serving to draw the tape tight through a hole in the blackened card. I enclose you the whole apparatus arranged in this manner, together with a few fibres of the Vigonia wool, which exhibit the colours in great perfection, constantly giving 14½ as the characteristic number. The directions for the use of the instrument might be engraved and printed on the card if it were thought desirable.
I also take the liberty of forwarding to you a letter which I have just received from a French gentleman, who claims the protection of the Royal Society. You will best judge whether the case requires or admits any exertion of your well-known liberality and kindness.
Believe me, dear Sir, with the highest respect and esteem, your faithful and obedient Servant.
DR. THOMAS YOUNG TO SIR JOSEPH BANKS.
Worthing, October 6, 1810.
My dear Sir,—I shall be most happy in assisting you to form a judgment from your own observation of the utility of my little instrument; but I cannot forbear to trouble you with a few specimens of wool, which I imagine will exhibit the appearances so obviously as at least to convince you of the perfect practicability of the method. You will observe, by merely looking through them at a candle, that there is a manifest difference in the size of the rings, and if the colours are not sufficiently conspicuous when the card is used, the central hole may be made a little larger with a bodkin; and a common pair of spectacles, such as you would use in mending a pen, will be amply sufficient for remedying the flatness of the eye.
I do not apprehend that the different magnitude of the different fibres of the same fleeces is any objection to the use of the instrument; on the contrary, it possesses the singular advantage of detecting at once the inequality where it exists, and of giving the mean dimensions of the whole at the same time where the difference is not too great. I have mixed together, for example, two small specimens, which measured separately 21 and 31. The mixture, though evidently irregular, gave the dimensions of about 24, varying from 23 to 27, according to the part of the lock which was to be examined, and this is surely a much greater inequality than can ever exist in any contiguous part of the same fleece. But, however this may be, the fact is that the circumstance does not actually destroy the validity of the indications of my micrometer, as I shall further exemplify to you by an account of my examinations of some specimens of the finest wool, with which I have been favoured by Mr. H. Sheppard, an ingenious manufacturer at Frome, Somersetshire. You are, perhaps, better acquainted than I am with the history of Mr. Western’s flock, which stands in so elevated a situation between the Saxon and the Spanish productions.