XX CONTENT S. 



DECEMBER 1797. 



I.. Concerning the fpontancmis AAion ot concentrateci Sulpliuiic Acid on Ve- 

 getable anJ Animal Suhftances ; its Aftion vipon Alcohui, and die Formation 

 of Ether. By Citizens Fiurcroy ami Vauquelin — P- 3^5 



oviniicin.ai llln.ln■^.vi.. < i^i.u.. w. .iilpliuric acid on fome vegetalile _- 



more complicated. New path opened for the analyfis of vegetables. Popular theory of ether 

 trrontocs. Experiment d<.tail:d. Induiftions. The true theory, as pointcJ out by cxpeiiment. 



II. On the Multiplier of Eleiftricity. By the Inventor, Mr. Cavallo : with 

 Obl'ervations — — — — P- 394 



Qiiotation refpef^lng the fplnning indiiiment. It differs in principle fr in the multiplier, and is a 

 condenfer. The multiplier does not demand a (lock of eliflricity, b"? operates by means of an 

 abfolutcly fmall quantity. Hiilory of inllruments for (hewing utak c!t.;^ricily. Compenfations in 

 the jar, the conjugate conductors, the can and chain, the eleArical well, ribbands, and (ilk llock- 

 ingf, vindicating cieftricity, and the elciSrophorc. Firft procefs of diiuMing. Volta's condenfer. 

 Bennet's doubler. Mechanical doublcrs of Darwin and N'ichollon. Their ambiguity. Cavallo's 

 ver)' perfeft condenfer, — does not remove the ambiguity of the doubler — neither does the fpinning 

 inftrument, which is an improvement on the condenfer. C.ivallo's mtiltiplur; operation and 

 power. Uncertainty of the doubler exifts in the other inftruments, though the doubler alone can 

 (hew it. 



HI. A Memoir on certain Methods of Economy, and Improvement in the 

 Manufadure of Hats. By Citizen Chaiifiier — — p. 399 



Political confidcratior.s. Art of the hatter. Operation of felting explained by Monge. Why cock 

 and hen feathers are inferior to thofe of geefe. Probable remedy. Sulphuric acid io the bath 

 for filling hats. Advantages. Stiffening. 



IV. D)iibts concerning the Exillence of a new Earth in the Mineral from 

 New South Wales, examined by Wedgwood in the Year 1790 p. 404 



"Examination of the Sydney earth, by Klaproth — by Wedgwood — Contraft of the experiments of 

 both. Thry did not examine the fame fubllance. 



V. A philofophical Memoir, containing, i. Experiments relative to the Pro- 

 pagation of Sound in different fofid and fluid Mediums. — And, 2. An 

 experimental Enquiry into the Caufe of the Refonance of Muficai Inftru- 

 ments. By iVlr. I'errole: with Annotations — P'4ii 



TranfmilCon of found through wood — metals — firings — and other folids; — through fluids. Refonant 

 property of various bodies. Undulations of the air, and of fonoroiis bodies. Whether air be the 

 medium of found. Why found is bcft heard in ths night. Obfervations relating to an acouftic 

 tube. Sonorous bodies vibrate. On the external ear, and the tympanum. General requifites of 

 an inftrumcnt for magnifying found. 



VI. Concerning the Steam Engine, as originally invented by the Marquis of 

 Worceller, and the Improvements lince made in Steam Engines without the 

 Pifton, or Lever. With a Defcription of an Engine of this Kind conftrufted 

 by Mr. Peter Kcir, of Kentilh-Town — — p. 419 



Marquis 



