68 Scientific Intelligence. 



5. On the Action of Zinc on dilute Sulphuric acid. — The curi- 

 ous intervention of a third substance in chemical reactions has 

 long been noticed. In the absence of moisture, for example, phos- 

 phorus may be distilled unchanged in oxygen and in the absence 

 of nitrous acid nitric acid has no action upon either silver or cop- 

 per. From this stand-point, Pcllixger has studied the action 

 of zinc upon sulphuric acid. The zinc was purified by three dis- 

 tillations in vacuo, in a tube of hard glass. The acid was puri- 

 fied by diluting with three times its mass of water and boiling 

 for six hours in a flask provided with an inverted condenser. A 

 sphere of this zinc 1*25 grams in mass, lost in this acid of specific 

 gravity 1-179 only five milligrams in sixty minutes. The conclu- 

 sions of the paper are as follows: (1) Pure zinc with a perfectly 

 smooth surface is not acted on by dilute sulphuric acid which has 

 been submitted to prolonged boiling; (2) pure zinc with a rough 

 surface is readily acted upon, but in a less degree by acids 

 which have been boiled than by those which have not; (3) 

 oxidizing agents such as electrolyzed sulphuric acid, hydrogen 

 peroxide and nitric acid, increase the rate of solution ; (4) reducing 

 agents such as hydriodic acid almost entirely prevent solution, 

 those containing sulphur however, like sulphurous oxide, being 

 without effect ; (5) it is not improbable that when zinc with a 

 rough surface dissolves in dilute sulphuric acid, persulphuric acid 

 acting by its presence is the cause of the solution; and (6) in all 

 probability pure dilute sulphuric acid at ordinary temperatures 

 would be entirely without action on metallic zinc whether the 

 surface of the metal were rough or smooth. — J. Chem. £oc.,'lvii, 

 815, Sept., 1890. G. f. b. 



6. New Melting-point Apparatus. — An improved melting-point 

 apparatus has been devised by Christomanos, consisting of a 

 two-necked bottle containing mercury, which can be heated in an 

 air-bath. Through one of the openings a thermometer passes 

 and also a wire from a voltaic cell. Through the other passes 

 the drawn out end of a glass funnel. The substance to be experi- 

 mented upon is placed in this funnel in the fused state and 

 allowed to solidify. The space above it is then filled with mer- 

 cury and the funnel is introduced into the bottle. The second 

 wire from the battery connects, through a vibrating bell, with the 

 mercury in the funnel. Upon raising the temperature of the bot- 

 tle to the fusing point of the substance, contact is established 

 between the two portions of mercury and thn bell is made to 

 ring. The temperature of the mercury in the bottle is then 

 noted. — Ber. Berl. Chem. Ges., xxiii, 1093, April, 1890. 



G. F. B. 



7. Chemistry, Organic and Inorganic. By Charles Loudon 

 Bloxam. 7th Edition, revised and edited by John Millar Thom- 

 son and Arthur G. Bloxam. 8vo, pp. xii, 799, Phila., 1890. 

 (Blakiston). — To the special features which have made Bloxam's 

 chemistry so well known among chemists, the present edition 

 adds new matter in the organic part, such as Raoult's method for 



