76 Progress of Invention. 



hydrogen does not contain a trace of either zinc or mercury ; and 

 being quite free from acid, it remains for a long time without 

 decomposing. 



Improved Electrotype Process. — Christofle and Bouillet, of 

 Paris, have introduced three great improvements into the electro- 

 type process. They add to the silver bath sulphuret of carbon, or 

 an alkaline sulphuret, which produces a small quantity of sulphuret 

 of silver ; and this, for some reason not yet explained, causes the 

 silver deposit to be, not dim and lustreless, but as brilliant as if it 

 had been carefully burnished. They add to the sulphate of copper 

 bath a moderate quantity of gelatine, which, for some reason, also 

 as yet unexplained, causes the copper deposit to be as compact and 

 dense as the very best rolled sheet copper. And lastly, they secure 

 very great economy, by attaching plates of lead to the platinum 

 wire, which forms the interior skeleton of the mould used for the 

 production of articles in relief. The results produced by this 

 modification of M. Lenoir's process affords products yet more per- 

 fect than those obtained by casting and chasing. 



Reproduction op Designs on Glass. — The decoration of por- 

 celain with designs embracing every grade of excellence, and at a 

 very trifling cost, compared with the beauty of the products, has 

 long been practised in this and other countries. But, hitherto, 

 glass appeared to be incapable of receiving any kind of orna- 

 mentation except by methods tedious, difficult, and expensive. It 

 is likely, however, that such is now no longer the case, as a process 

 has been invented in France, by means of which engravings are 

 transferred to glass with nearly the same facility as they have 

 hitherto been transferred to ceramic products. In the case of 

 porcelain, fine lined copper plate engravings on tissue paper are 

 applied to the surface of the article, the engraved side inwards ; 

 and the paper having been washed away, the lines of the engraving 

 which still adhere to the porcelain are permanently attached by 

 firing and glazing. In the case of glass, this process requires to be 

 modified ; a fine lined engraving would not answer, and hence, one 

 having lines of sufficient depth is used. Also, stearates and oleates 

 are added to the silicates and borosilicates, which are intended to 

 support, or to fuse the coloured or colouring oxides, for the purpose 

 of giving to the enamels the thickness which glass requires them 

 to have ; and a solution of resin in ether or benzine is added. The 

 engravings on paper are produced by means of engi'aved rollers ; 

 and, after having been treated very much in the same way as with 

 porcelain, the glass is placed in the furnace, and thus the most 

 beautiful results are obtained with certainty, ease, and economy. 



Oxygen in a Different State in Different Peroxides. — Cur 

 knowledge regarding the different conditions in which oxygen may 

 exist is receiving constantly new accessions. Not the least impor- 

 tant of these is the fact recently discovered, that the oxygen in the 

 peroxide of manganese is in a very different state from that in the 

 peroxide of barium : a circumstance which is strongly confirmative of 

 the theory of Schonbein, that oxygen may exist in two opposite 

 states, which he has termed ozone and antozone, oxygen in its ordi- 



