CHEMISTRY. 139 



copper- zinc couple of Gladstone and Tribe reduces potas- 

 sium chlorate readily, but is entirely without action on the 

 perchlorate. By means of this reaction he has studied the 

 character of the decomposition of the chlorate by heat, and 

 proves that no perchlorate is formed when manganese diox- 

 ide is used. 



Shaw and Carnelley have examined the question of the 

 protecting action of copper sulphide upon metallic copper. 

 Two pieces of this metal were taken, exactly alike, one of 

 them immersed in dilute ammonium sulphide till coated with 

 copper sulphide, and then both placed in water, with and 

 without access of air, and in various saline solutions. The 

 results showed that previous washing with ammonium sul- 

 phide increases the action of distilled water on copper when 

 exposed in open vessels, but lessens it when air is excluded, 

 while in the case of saline solutions the action is diminished 

 even when air has free access. 



Muir has studied the action of various saline solutions upon 

 lead, from which he draws the general conclusion that the 

 action upon lead of those saline solutions which he has exam- 

 ined results, in the first place, in the production of a salt other 

 than the hydrocarbonate ; that carbon dioxide, slowly ab- 

 sorbed from the air, produces hydrocarbonate, which is pre- 

 cipitated ; and that certain salts, such as ammonium nitrate 

 and calcium chloride, accelerate the production of the soluble 

 lead salt. 



Hermann has made an extended investigation on the tanta- 

 lum group of metals, and has discovered a new metal in this 

 group, which he calls Neptunium, and which has an atomic 

 weight of 118. The mineral in which the metal was detect- 

 ed was columbite, from Haddam, Connecticut. 



The same investigator takes occasion to reaffirm the 2;en- 

 uineness of his discovery of another metallic element, Ilme- 

 ?iium, announced some years ago. This announcement was 

 at the time strongly opposed by the eminent chemists Rose 

 and Marignac, and with such plausibility that Hermann pub- 

 licly withdrew his claim to a new discovery. Hermann, in 

 the same publication in which he announces the discovery 

 of neptunium, takes occasion to reaffirm the genuineness of 

 his former discovery of ilmenium, and points out that his emi- 

 nent critics were in error, having been misled by employing 

 impure materials. 



