Chemistry and Chemical Arts. 143 
It is imstantly converted into the red salt by ee action of hot 
water. 
The red salt is composed of: 
Silver, . é : ; é ‘ E 0.51062 
Iodme, . . .. : : : - : 0.29813 
Oxygen, é : - : é : 0.17000 
Water, . ‘ 0.02125 
Nitric acid eplapeli’ in aie pepention land adel by heat, con- 
verts these two salts into the neutral orange salt, which is compo- 
sed of: 
Silver, . , 4 ‘ j : ‘ 0.42313 
Todines {290 : 4 : : 2 0-36237 
_ Oxygen, 3 : : 0.21448 © 
It is therefore a seutial sialiptlbon’ salt. Water decomposes it 
into an insoluble, basic salt and into pure hyper-iodic acid, which re- 
mains in the liquid and does not contain a trace of silver. The resi- 
due is yellow, when cold water is used, and red when the solution is 
heated.—Idem. 
18. Boracic Acid of Tuscany.—lIt occurs chiefly in the lakes 
of Montecerboli and of Castel-Nuovo upon the royal road from Vol- 
terra to Massa, situated in an arid soil covered with fragments of a 
stratified shelly limestone, mingled with pyrites and slates. It also 
comes to the surface in gaseous currents, which have a temperature 
of 120° or 140° C. The annual produce is 700,000 pounds, 
which yields a profit of 300 francs to the 1000. The manufacture 
is due to the chemist Horrer, who made the discovery in 1777.— 
Idem. 
19. Manufacture of Carbonate of Soda, by Pruxxner. (Ann. 
de Scuweriecer. )—Commence by changing the calcined sulphate 
of soda into sulphuret of sodium, by heating it to redness with pul- 
verized charcoal. Dissolve the sulphuret and add to the warm li- 
quor, oxide of copper. Filter and evaporate the liquid until its Sp. 
gr. =1.41 or 1.48. On leaving the solution for twenty four or for- 
ty eight hours, the undecomposed sulphate of soda crystallizes. 
Evaporate the supernatant fluid to dryness. This process gives for 
one hundred of sulphate of soda about sixty five of crude caustic so- 
da. ‘To convert this into carbonate, it is heated gradually to red- 
ness with charcoal. Metallic copper as well as its oxides may sepa- 
