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Ordinary Meeting, January 21st, 1862. 
E. W. Binney, F.R.S., F.G.S., Vice-President, in the Chair. 
William Arthur Darbishire, Esq., B.A., was elected an 
Ordinary Member of the Society. 
A Communication, “ On the Action of Nitrate of Sodium 
on Sulphide of Sodium at Different Temperatures,” by Dr. 
Ph. Pauli, Union Alkali Works, St. Helens, Lancashire, 
was read by Professor Roscoe. 
The mother liquor obtained in the manufacture of soda 
ash contains, as is w r ell known, large quantities of sulphide 
of sodium. In order to oxidise that compound, nitrate of 
sodium is used. As long as the boiling point of the liquid 
is between 280 — 290° F., the sulphide is quietly oxidised to 
sulphate, nitrite of sodium being formed. 
But if the nitrate is added when the temperature of the 
boiling liquid is about 310° F., a violent evolution of ammonia 
takes place, according to the following equation — 
2 Na S + Na NO 6 + 4 HO = 2 Na S0 4 + NoHO, -f NH 3 
As the liquor contains a large amount of sulphide, the 
quantity of ammonia is so considerable that it may prove 
worth while to connect the evaporating pot with a tower 
filled with coke, over which a stream of water or dilute acid 
is running. 
If the nitrate be added when the liquor has been heated to 
a temperature much above 310°, a violent evolution of pure 
nitrogen occurs. 
5 Na S + 4 Na NO 6 + 4 HO = 5 Na SO 4 + 4 Na 0 2 H + 4 N. 
Proceedings— Lit. & Phil. Society— No. 9.— Session 1861-62. 
