VOL. XII.] . PHILOSOPHICAL TRANSACTIONS. 443 



about 30° : whence it appears that the moon's centre was then in the periphery 

 of the sun, and that the Hne through the centre was equal to the sun's semi- 

 diameter. But after the middle of the echpse there was found some change in 

 the diameter of the shadow ; for the shadow appeared a Httle more convex, so 

 that the diameter was shorter, though almost insensibly. 



The making of Microscopes. By Mr. Butter/ield, Instrument maker to the 



French King. N° 141, p. 1026. 



I doubt not but you may be as busy at London, as we are here, in making 

 of microscopes of the kind lately brought out of Holland by Mr. Huygens, 

 of which I have several sorts ready made. I have tried several ways for the 

 making of glasses of the size of a large pin*s head, and less ; as in the flame 

 of a tallow-candle, and of one of wax. But the best way of all I have yet 

 found, to make them clear and without specks, is with the flame of spirit of 

 wine well rectified, and burned in a lamp. Instead of cotton, I make use of 

 very small silver wire, doubled up and down like a skein of thread; which 

 being wet with the spirit of wine, and made to burn in the lamp, gives through 

 the veril of the lamp a very ardent flame. Then take the beaten glass, being 

 first washed very clean, on the point of a silver needle filed very small, and 

 wet with spittle. Hold it thus in the flame till it be quite round, and no 

 longer for fear of burning it ; and if the side of the glass next the needle be 

 not melted, you may put it off and take it up with the needle on the round 

 side, presenting the rough side to the flame till it be every where very round 

 and smooth ; then wipe and rub one or several of them together with soft 

 leather, which makes them much the better. Then put them between two 

 pieces of thin brass, the apertures very round, and that towards the eye almost 

 as large as the diameter of the glass ; and so place it in a frame with the object 

 conveniently for observation. 



Improvement of Sir Samuel MorelancTs Speaking Ti-umpet, &c. By Mr. John 



Conyers. N° 141, p. 1027- 



Having some years since tried to make one of Sir S. Moreland's speaking 

 trumpets of tin, that is, tinned iron plate ; and finding it to serve, as well as 

 copper or glass ; I next thought of several ways for reducing it to a more con- 

 tracted form, without abating its power. In consequence Dr. Goddard pre- 

 sented to the Royal Society, at one of their meetings, held at Arundel House, 

 the reflecting trumpet here described. It consists of two parts. The utmost 

 Bb (fig. 6. pi. 12.) is a large concave pyramid, about a yard long, or of any 

 manageable length, open at the base b, and closed, not with a flat, but a con- 



