138 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



form powder, consisting of lemon-yellow clear grains, with- 

 out crystalline form. Analysis showed them to contain for- 

 ty-eight per cent, of silver. 



Boisbaudran, in a paper on the physical properties of his 

 new metal, gallium, states that it fuses at about 4-29.5, and 

 therefore liquefies readily when held in the hand. It main- 

 tains the liquid condition with great persistence, a fragment 

 having remained liquid for the month of February, capable of 

 being united and separated, like mercury. When solid it is 

 remarkably hard, resembling aluminum. It crystallizes read- 

 ily, does not oxidize at a red heat, and is not volatile. Its 

 density is 4.7, approximately. 



Boisbaudran subsequently presented to the French Acad- 

 emy a specimen of gallium crystallized in the form of octa- 

 hedrons truncated at the base. They appear to be clino- 

 rhombic. 



Cresti has described a very delicate test for copper. Two 

 small wires, one of zinc the other of platinum, connected at 

 one end, are placed in the solution suspected to contain this 

 metal. A black deposit appears on the platinum wire. To 

 test this, it is washed and placed while still moist in a mixt- 

 ure of hydrogen-bromide gas and bromine vapor (such as is 

 obtained by acting on potassium bromide by strong sulphu- 

 ric acid). The deposit, if copper, becomes a deep violet liquid, 

 especially distinct when placed on a white plate, which the 

 author believes to be a solution of cuprous bromide in hy- 

 drogen bromide. Copper may thus be detected in a few 

 cubic centimeters of a one-millionth solution. 



Thudichum and Hake have made a series of experiments 

 on metallic copper and its power of occluding hydrogen, 

 with a view to test the question of its influence upon the ac- 

 curacy of those organic analyses in which it is used. From 

 the results obtained they conclude (l) that copper-wire gauze 

 which lias never been used, when oxidized and subsequently 

 reduced in a current of hydrogen, being allowed to cool in 

 the gas, occludes a very appreciable amount of it, being 

 about 0.6 milligram per 100 grams of copper ; and (2) that 

 the gauze loses this property after several repetitions of the 

 process. The error introduced into analysis is therefore triv- 

 ial. 



Ecclcs, working in Thorpe's laboratory, has found that the 



