PROCESS FOR' FABRICATING ALUM. Q^ 



horizon, then take the firft inftrument, and corred the ob- 

 fervation ; and fo continue to ufe the inftruments alternately 

 till the fun lliall arrive at his greateft altititde. 



If the fun*s altitude were taken, when off the meridian, by This method 

 two obfervers, in the manner above mentioned, in order to j^j^^^^j^^^J^^ 

 find the hour from noon, it might greatly add to the accuracy time. 

 of that important problem. 



REMARKS. 



From the above ftridures it appears, that navigation might 

 receive many improvements from an inftrument that would 

 take in the largell angle, and admit of being accurately ad- 

 jufted. The latitude and time of the day might then be de- ' 

 termined with greater precifion than at prefent, and the limits 

 of the method of finding the longitude by the lunar theory 

 would be enlarged. 



EZEKIEL WALKER, 



Lynn, December 22 J 1803. 



(To he continued in a future conununicatioii.) 



ERRATUM. 



Vol. VI. p. 219. near the bottom, for 120^', read 180^. 



XIII. 



New Procefs for fabricating Alum artificially and without thi 

 AJfifiance of Evaporation. By Cit. Curaudau, Correfpond- 

 ing Member of the Society of Apothecaries of Paris *, 



A REPORT was made to the National Inftilute in Friic- ^ 

 tldor of the year 9, by Citizens Guyton aad Vauquelin, on 

 a new procefs of Citizen Curaudau, for the artificial fabrica- 

 cation of alum. As this report is not generally known, we 

 haften to communicate it to our readers. 



Citizen Curaudau propofes, in the fabrication of alum, Procefs employ- 

 to employ one hundred parts of clay, and five of muriate of ^,** V Cit. ^ 

 foda, diluted with a quantity of water fufficient to give apafiy make alum ' 

 confiftence to the mixture. It is then made into loaves, with artificially. 



100 clay and 5 



* From the Annales de Chimie, Floreal, An» Xh Noi 137. kneaded with 



which waterj theloaval 



