xiv, CONTENTS. 



On the propjigation of the Iheep with the goat. Treatment of iheep. On various animals ufed for 

 food] &c. 



XIV. On the native Iron of Peru, and on Mercury contained in Sea-Salt. By 

 Profeffor Prouft of Madrid - "- - P- 374 



XV. Not« concerning the Earthquake in Peru. By M. Cavanilles ?■ 377 

 Account of Books - - - _ _ p. j^p 



DECEMBER 1799. 



Engravings of the following Objefts: i. The Gazometer of Seguinj and, 2. 

 Figures illuftrative of the theory and fabrication of Spirit Levels. 



I. An Inquiry concerning the Weight afcribed to Heat. By Benjamin Count of 

 Rumford, F.R.S. &c. - - - P- 381 



Upwards of four thoufand grains of water was counterpoifed againft a like quantity of weak ardent 

 fpirit, in bottles of the fame magnitude, hermetically fealed ; the temperature being 6i°. The 

 apparatus being then removed into a room at the temperature 29° the water froze and preponderated 

 by upwards of one-tenth of a grain. The equilibrium was reftored when the ice was fufed again in 

 the warm room. Sufpicions of fallacy, hov/ever, led the inventor to other refearches. By expofing 

 the balance, loaded with two balls of gilt brafs, to different temjieratures, it was proved that no un- 

 equal expanfion of the arms had talcen place. On repeating the original experiment with mercury, ' 

 inttcad ot^ ardent fpirit, no change of equilibrium enfiied from the congelation of the water; and 

 when again with the moft minute attention to the equality of temperature in three mafles, of water, 

 of mercury, and of diluted ardent fpirit which were refpeftively put in equilibtio at 60? and' at 30° 

 no alteration was found at either temperature. Obfervations and remarks. 



II. On the Plants ufed by the Ancient People of Europe to poifon their Arrows. 

 By C. Ch.'Coquebert - - - P- 390 



III. Experiments to determine the Quantity of Tanning Principle and Gallic 

 Acid, contained in the Bark of various Trees. By George Biggin, Efq. 



p; 3:92 



The tanning principle was feparated by quick infufion, and the gallic acid by fubfequent infufion for a ^ 

 longer time. The quantities of the former were afcertained by its precipitation with glue, and 

 the latter was judged of from tbc intenfity of colipHr it afforded with fulphate of iron. Refuhs of 

 trials on twenty-one faaiples of barksi 



IV. On the Plumb Line and Spirit Level. ByM'.Ghezy - . P' 396 



Defcription of the plumb line. _ Its degree of accuracy. Spirit level defcribed, its qualities invefti- 

 gated. Method of grinding its inner furface. Annotations theoretic and praftical. 



V. A Chemical Examination of the Bath Waters. By George Smith Gibbes, 

 M.D. F.R.S. (continued) . - - - p. 403* 



DeteAioB of a confidfirable portion offilex in the Bath waters. 



VI. 



