LITERARY NOTICES. 307 



motive power, which was very severely commented on by Dr. Ritchie, a very 

 successful and talented experimenter on the same subject. Papers were sub- 

 sequently read by Messrs. Slevely, Wheatstone, Addams, and others ; but 

 we have not room for a more extended notice. 



In section B Mr. Watson read a paper on the phosphate and pyrophos- 

 phate of soda, after which was described and exhibited a new form of blow- 

 pipe by Mr. Ettrick, so constructed as to furnish a constant blast independ- 

 ently of hydrostatic pressure, accomplished by small bellows worked by a 

 wheel and pinion, and fitted with a stop-cock to the tube connecting the 

 bellows and reservoir. Mr. Herapath followed with some remarks on the 

 chemical constituents of the Bath waters, and afterwards with a short paper 

 on the aurora borealis, which he attributed to the escape of electricity in 

 streams from an excited cloud enveloped in a dry atmosphere. This view 

 was strongly opposed by Dr. Dalton, on the ground that the phenomena 

 occur frequently when clouds are altogether absent. 



Dr. Hare next described his apparatus for the analysis of gaseous mix- 

 tures. It consists of two distinct parts, his eudiometer and calorimeter, in 

 the former of which he measures and confines, and, by the latter of which, 

 he fires the mixture. The combustion is not produced, as in the case of the 

 common eudiometer, by an ordinary electric spark, but by igniting with the 

 calorimeter a fine platinum wire, which traverses the gaseous mixture. Dr. 

 Hare applies his calorimeter to the blasting of rocks. By this machine the 

 powder can be fired at a great distance, and several trains also at the same 

 instant, of course, without endangering the lives of quarrymen ; and, should 

 an immediate explosion not take place upon setting the calorimeter in action, 

 by replacing this instrument in the inactive state, which is done in an instant, 

 the train may be approached without fear that ignition will ensue,' a thing 

 which, according to the ordinary modes of blasting, can seldom be done with 

 impunity. He also alluded to an apparatus, in which silicon and boron can 

 be readily obtained by igniting with his calorimeter potassium enveloped by 

 the fluosilicic or fluoboric gases. 



A profoundly scientific paper was read by Mr. Exley on the propriety of 

 reducing chemistry to mathematical principles, which was highly praised by 

 Drs. Dalton and Thomson of Glasgow; but it was too difficult to be gene- 

 rally understood by a mere hearing of it. Mr. Babbage exhibited an old 

 thermometer discovered in Italy, which occasioned some interesting conver- 

 sation on thermometers generally, and their application to meteorological 

 purposes. 



An essay on gaseous interference, by Dr. Charles Henry, was next read. 

 If oxygen and hydrogen be mixed, and brought into contact with spongy or me- 

 tallic platinum, the combination of these gases is very rapidly effected, and, if 

 mixed in the proper proportion, they are converted usually with the pheno- 

 mena of ignition, although into water. It is also well known that if into an 

 atmosphere of oxygen and hydrogen, mixed in the ratio necessary for forming 

 water, certain other inflammable gases be introduced, the combination of the 

 oxygen and hydrogen is, if not altogether suspended, at least materially inter- 

 rupted. This is what Dr. Henry denominates gaseous interference. The 

 cause of this remarkable effect has at different times attracted the attention of 

 eminent chemists. Dr. Turner has ascribed it to the soiling of the platinum 

 by the interfering gas, Dr. Faraday to some peculiar condition induced in the 

 metal ; while Dr. Henry himself, at a period long prior to the present, con- 

 ceived it to arise from the fact of carbonic oxide and olefiant gas having a 

 stronger affinity than hydrogen for oxygen gas. In his present paper, Dr. 

 Henry investigated the entire question. As a general rule, it may be laid 

 down that the interfering influence of the gas bears an inverse relation to the 

 energy with which the platinum acts, and the degree of heat conditions, how- 

 ever, which may be considered as identical. The diminution, and even disap- 

 pearance, of interference at high temperatures, Dr. Henry attributes to a 



