VOL. LXXII.] PHILOSOPHICAL TRANSACTIONS. 1 65 



by the accurate and numerous experiments of Sir George Shuckburgh. His 

 valuable paper is inserted in the 69th vol. of the Philos. Trans. On considering 

 this paper, I thought it possible to construct a thermometer with proper apparatus, 

 which, by means of boiling water, might indicate the various gravity of the at- 

 mosphere, viz. the height of the barometer. This thermometer, with the suit- 

 able apparatus, might, I thought, be packed into a small and very portable box, 

 and I even flattered myself, that with such an instrument the heights of moun- 

 tains, &c. might perhaps be determined with greater facility than with the com- 

 mon portable barometer. My expectations are far from having been disappointed, 

 and though the instrument which I have hitherto constructed has various defects, 

 I have however thought of some expedients which will undoubtedly render it 

 much more perfect ; I shall then present to this Society a more particular account 

 of it, and also of the experiments which I intend to make with it. The instru- 

 ment in its present state consists of a cylindrical tin vessel, about 2 inches in 

 diameter and 5 inches high, in which vessel the water is contained, which may 

 be made to boil by the flame of a large wax candle. The thermometer is fastened 

 to the tin vessel in such a manner, as that its bulb may be about 1 inch above 

 the bottom. The scale of this thermometer, which is of brass, exhibits on one 

 side of the glass tube a few degrees of Fahrenheit's scale, viz. from 200° to 

 21 6°. On the other side of the tube are marked the various barometrical 

 heights, at which the boiling water shows those particular degrees of heat which 

 are set down in Sir G. Shuckburgh's table. With this instrument the barome- 

 trical height is shown within -V of an inch. The degrees of this thermometer 

 are somewhat longer than ~ of an inch, and consequently may be subdivided into 

 many parts, especially if a nonius is used. But the greatest imperfection of this 

 instrument arises from the smallness of the tin vessel, which does not admit a 

 sufficient quantity of water: and I find, that when a thermometer is kept in a 

 small quantity of boiling water, the quicksilver in its stem does not stand very 

 steady, sometimes rising or falling even half a degree; but when the quantity 

 of water is sufficiently large, for instance is 10 or 12 ounces, and is kept boiling 

 in a proper vessel, its degree of heat under the same pressure of the atmosphere 

 is very settled. 



END OF THE SEVENTY-FIRST VOLUME OF THE ORIGINAL. 



/. On a new Kind of Rain. By the Count de Gioeni, an Inhabitant of the 3d 

 Region of Mount Etna. From the Italian. Vol. LXXIl, Anno 1782. p. 1. 

 The morning of r«»J 24th inst. (April 1781) exhibited here a most singular 

 phenomenon. Every place exposed to the air was found wet with a coloured 



