52 Scientific Intelligence. 



Bandrowski has also made a study of the emission of light 

 from mixtures of potassium and sodium sulphates when they 

 crystallize, the circumstance having been originally observed by 

 Rose. Curiously enough, neither of the single sulphates gives 

 the phenomenon, and the author concludes that the formation of 

 a double salt, 2K Q S0 4 . Na Q S0 4 is the necessary condition. He 

 promises further results in this interesting field. — Zeitschr. Phys- 

 ihal. Chem., xvii, 234. h. l. w. 



5. The Preparation and Properties of Titanium. — Moissan 

 has succeeded in preparing titanium, in a purer state than it has 

 heretofore been known, by reducing the oxide with carbon in his 

 electric furnace. With a current of 100 amperes and 50 volts, a 

 fused or crystallized oxide of an indigo-blue color is obtained. 

 With 300 or 350 amperes and 70 volts a perfectly fused mass of a 

 bronze-yellow color, the nitride, Ti Q N Q , of Friedel and Guerin, is 

 produced. At still higher temperatures the nitride is decomposed, 

 so that with a current of 1,200 amperes and 70 volts, either the 

 carbide, TiO, or titanium itself is obtained, according as to whether 

 carbon is in excess or not, and these products are entirely free 

 from nitrogen. The titanium was obtained in a fused condition, 

 but Moissan states that it is the most refractory body that he has 

 as yet obtained in his electric furnace, being more infusible than 

 vanadium, and still more so than chromium, tungsten, molyb- 

 denum and zirconium. The purest titanium obtained in this 

 way contained about 2 per cent, of carbon, bnt was practically 

 free from other impurities. The fused titanium forms a brittle 

 mass, harder than quartz, showing a brilliant, white fracture. 

 Its density is 4-87. When heated, it combines with chlorine and 

 oxygen with incandesence, and with nitrogen with some eleva- 

 tion of temperature. Nitric and hydrochloric acids attack it 

 slowly even when hot, while aqua regia and sulphuric acid dis- 

 solve it much more readily. When titianium is heated in the 

 electric furnace with boron and silicon, there are formed borides 

 and silicides, either fused or crystallized, which are as hard as 

 diamond. — Bull, jSoc. Chim., Ill, xiii, 959. h. l. w. 



6. Practical Proofs of Chemical Laios ; by Vaughan Cornish, 

 12mo, pp. 92. London and New York, 1895. (Longmans, Green & 

 Co.) — This small text-book gives a series of experiments by which 

 students may verify certain fundamental laws of chemistry, includ- 

 ing conservation of mass, definite proportions, equivalent propor- 

 tions and multiple proportions. The experiments are well 

 devised and, for the most part, satisfactorily described and ex- 

 plained. Results obtained by students, showing a good degree 

 of accuracy, are given throughout the book, and the author states 

 that these pupils were mostly between twelve and eighteen years 

 of age. Such young pupils would probably gain some knowledge 

 of quantitative analytical processes by pursuing such a course, 

 but it seems doubtful if most beginners would fully realize its 

 significance, especially since chemical equations and formulae are 

 excluded on the ground that they are inadmissible in an exami- 



