SCIENTIFIC NEWS. 281 



On the life of Sulphate of Soda in tlie Manufactory ofGlafs. 

 x By Pajet-Descharmes *. 



Since the notice which was given in the Journal de Phyfique ufeof fulphatt 

 that fulphate of foda might be ufed, without preparation or of foda in glaft 

 any intermediate agent, in the fabrication of filiceous glafs, ma lnfi * 

 Cit. Pajot-Defcharmes has thought fit to publifh the refult of 

 his principal experiments on the employment of this fait in 

 glafs-making. 



It appears from the experiments which this operator has 

 reported in the Journal de Phyfique, 



1. That fulphate of foda and fand alone, in various propor- 

 tions cannot fucceed. 



2. That fulphate of foda, mixed with pounded charcoal, in 

 the proportion of a tenth or twentieth part, yielded a yellow 

 glafs more or lefs black, of the nature of obfidian partes or 

 itones : the crucibles were then very flightly a6led upon. 



3. That equal parts of carbonate of lime, dried fulphate of 

 foda, and fand, produced a beautiful glafs, clear, folid, and 

 of a pale yellow : the crucibles were then very little corroded. 



Cit. Pajot-Defcharmes obferves, that notwithftanding the , 

 pains he took, he could never obtain a glafs with fulphate of 

 foda that was not of a yellowifh green, whereas muriate of 

 foda (fea-falt), treated in the fame manner as fulphate of foda, 

 always produced a glafs of a light blue tinge inclining more or 

 lefs to green. 



Cit. Pajot-Defcharmes propofes to treat more fully, in a 

 particular memoir, on all the experiments he has made on this 

 fubjecl. 



Ohfervations on the Necejfity of immerfing Seeds in Water in Times 

 of Drought. By Ant. Alexis Cadet-de-Vaux. f 



Franconville-la-Garenne, 2 Brumaire (Ocl. 23.) 

 To reap, we muft fow ; and, from the drought which has In dry f ea f ons ■ 

 prevailed for fix months, fowing is not eafy, for our gardens the feed grain ii 



in danger of pe- 

 * Abridged with remarks in the Journal des Mines, No. 69. "^5 in tliC 

 from a Letter from Cit. Pajot-Defcharmes, to J-. C. de la Metherie, gr U 

 in the Journ. de Phyfique, Vol. LII. p. 210. 

 f Decade Philofophique, No. 4. An. XI. 



are 



