INDUSTRIAL PROGRESS DURING THE YEAR 1875. lxxxi 



concludes that glucinum has an equivalence of two, and be- 

 longs to the magnesium group, while yttrium, erbium, ceri- 

 um, lanthanum, and didymium have an equivalence of four, 

 like aluminum, iron, chromium, and indium, their double at- 

 oms, also, like the latter, having an equivalence of six. 



Santesson has examined a series of niobium compounds, 

 and has minutely described the principal fluoniobates. 



Hammerbacher has succeeded in discovering the presence 

 of thallium in carnallite, though the quantity was too small 

 to enable him to isolate it. Rubidium and coesium were also 

 detected by the spectroscope in this and in sylvite. 



Hawes has made a chemical investigation of the trap-rocks 

 of the Connecticut Valley. The results show that the eject- 

 ed rock had originally the same composition, and hence, pre- 

 sumably, that wherever now found, it came in the first place 

 from the same source, and that a deep-seated one. Subse- 

 quent action has converted the dolerite into a diabase, the 

 principal action being upon the pyroxene, which was con- 

 verted into chlorite. The chief minerals composing the dole- 

 rite are pyroxene and labradorite sometimes anorthite 

 with a little chrysolite and apatite. Magnetite is also found 

 in these traps, in some of them to the amount of nearly four- 

 teen per cent. 



Terreil has proposed a new method of producing pure nick- 

 el salts on a commercial scale without the emploj^ment of 

 either hydrogen sulphide or ammonia. His process consists 

 of four operations : first, solution of the nickel in acid ; second, 

 precipitation of the copper by iron ; third, peroxidation of 

 the iron, and transformation of the metals into sulphates ; 

 and, fourth, precipitation of the iron by barium carbonate 

 and crystallization of the pure nickel sulphate. 



Treve and Durassier have experimented to ascertain the 

 relation which exists between the chemical composition of a 

 steel and its coercitive force. They find that up to a certain 

 limit (from 1 to 1.15 per cent, of carbon) the magnetic satu- 

 ration increases with the content of carbon. Durassier gives 

 a note of great practical value on the choice of steels for dif- 

 ferent purposes. 



Hartley has given a simple mode of assaying an iron ore 

 when the facilities of a laboratory are wanting. The ore is 

 balanced (on a rude pair of scales without weights) against 



4* 



