viii CONTENTS. 



JLeltcr-pvcrs dcfonbed. Bl -ck printing. Diftlnaions between letter-prcfs nnd Mock-pr!nffn^. 

 ' Copperplate piiiiiing. Cylinder printing. General view of the co-nmcrcial impcdi-nents to the 

 fiicctfs of inventions — Phyfical difficiilties— particularly wi'.h regard to cylinders — Remedies. 

 How far paucr iV.iinen and ciUico-printtts are prevented from ufing maoliinery by the opcrationi 

 of the Ex<.i!'c Laws. 



V. Aq Account of the Diamonds of Brazil. By M. D'Andrada — p. 24 



Defcription of the pnwince of Brazil, which affords diamonds. Hillory of the Jifcovery. N.itural 

 hillory of the diamond. Method of exploring. 



VJ. Abftraft of the' Specification of Mr. William Definond's new Method of 

 Tanning, with Obftrrvations lelative to that Subject — — p. 26 



Art of tanning. Method of obtaining the tanning principle, and the principle of aftringency, from 

 oak bark fip.irately — Criterions for dillinguilhing them. Procefs with ilrong hides— with lighter 

 Ikins. Tanning propofcd inllcad of tar for ropes, and fait for fiefti meat. Kcfleftions. Refuits of 

 aftual enquiry. Prdeut flatc of the invention. 



VII. Difcription and Account oF a new Prefs operating by the Aftion of Water 

 on the Fnnciple of the Hydroltatic Paradox. Invented by Jjfeph Bramah, 

 En ineer — — — — — 29 



Defcription of the inftrument, and its mode of aftion. Computation of its force. — Compared witU 

 a fcrew ; in theory — and in pradice.— Experiments or trials. 



VIII. The Procefs for giving a beautiful White Colour to Raw Silk, without 

 Scouring. By M. Baume — — — P* 3^ 



Illftorical fafts. Quality of Chinefe (ilk. Banm^'s procefs — 1. Killing the chryfalis — J. winding 

 off the filk on a reel. Apparatus for bleaching with marine acid and fpirit of wine. — The pro- 

 cefs. — f recautioDS in drying. — Chinefe filk probably bleached in this way. 



IX. On the Hydrometer of Baum^ — — — ?• 37 



Hydrometer for falts ; — and for fpirits. Deduftions of the fpecific gravities indicated by thefe in» 

 ftrumciite, difpofed in tables. 



X. Obferva'ions on the Soap of Wool, and its Ufcs in the Arts. By J. A, 

 Chaptaljinftitutor of the Polytechnic School -^ — P- 40 



Preliminary obfervations. Procefs for making foap of alkali and wool. Enumeration of the faifls. 

 Choice and preparation of materials. Management of the operation. Singular eSeA of this foap 

 on cottons. 



XI. Extraft of a Memoir concerning three different Species of Carbonated Hy- 

 drogenous Gas obtained from Ether and Alcohol by different Proceffes, for. 

 varded to the National Inftitute of France by the Society of Dutch Chemifts; 

 being Part of a Report read to the FirftClafs of the Inftitute by Citizen Four- 

 croy at the Sitting of the 26th Frimaire, 16th December 1796 — p. 44 



General accouat of the defiant gas. Procefs for obtaiaing it. Phenomena, 



6 Mathe- 



