Scientific Intelligence, Sfc. 227 



of the re-agents. He observed, that when the pyro-phosphate of 

 soda and the phosphate were precipitated by lime-water, the pyro- 

 phosphate of lime, when ignited, assumed a black colour, while the 

 common phosphate remained white. The author also mentioned, 

 that, contrary to what was supposed, pyro-phosphate of soda might 

 be kept in solution for, at least, a year and a half without being re- 

 converted into the usual phosphate. 



2. 3fr, Ettrick illustrated and explained an Improvement in the 

 Blowpipe, by which the blast of the common blowpipe was made as 

 equable as that by water pressure. 



3. Mr. Herapath gave the results of the Analyses of Two 

 Mineral Waters in the neighbourhood, and detailed his mode of 

 analysis. 



4. The same gentleman read a paper on the theory of the Aurora 

 Borealis. He stated that as far as he had observed this phenomenon, 

 it was always situated low in the sky, and in connexion with clouds. 

 Hence, he inferred that it is occasioned by electricity passing from 

 the clouds. This paper gave rise to a discussion, in which Dr. 

 Dal ton stated it as his conviction, from very numerous observations 

 that the Aurora is always high in the atmosphere, and that the 

 clouds referred to were not clouds but arches of darkness, through 

 which the stars might be observed, and produced by the contrast of 

 the light beneath. 



Tuesday, 23rd August. — 1. Mr. Exley read an exceedingly- 

 talented paper, developing a new theory of chemical combination 

 deduced from mathematical data, and demonstrated methematically. 

 The reading of this paper excited a very great degree of interest. 

 It promises to throw a great deal of light upon the theory of 

 chemistry. 



2. Dr. Charles Henry read an account of some experiments 

 made with a view to determine the mode in which certain gases act 

 in preventing the action of spongy platinum upon a mixture of 

 oxygen and hydrogen. The gases which he examined were carbonic, 

 oxide and olefiant gas. He found that carbonic oxide was the most 

 powerful, and that carbonic acid is always the result. Hence, it is 

 evident that oxygen and hydrogen are prevented from combining by 

 the superior attraction of the carbonic acid for the oxygen. Olefiant 

 gas he found not to be decomposed, and hence the attraction which 

 prevents the combination is not sufficiently powerful to form any 

 other. This explanation is corroborated by the fact that it requires 

 a very great proportion of the olefiant gas to produce the effect. 



3. Mr. Herapath stated some facts respecting the Arsenical 

 Poisons, and illustrated them by experiment. 



Wednesday, 24th August. — 1. Dr. Daubeny read a very copious 

 and interesting report on the present state of our knowledge with 

 respect to thermal waters. 



2. Mr. Mushet exhibited some specimens of metallic iron pre- 

 pared by exposing the ore to long continued heat with a small 

 quantity of fuel, and thus reducing it to the metallic state without 

 fusion. 



3 Mr. Johnston descril)ed paracyanogen and its componnds. 



Q 2 



