498 Chronicles of Science. [July, 



The picture may be changed to purple by a solution of chloride 

 of tin. 



Heat. — M. H. St. Claire Deville has been for many years occu- 

 pied with the curious subject of dissociation, and on May 1st he pre- 

 sented to the Academy of Sciences a memoir on the phenomena of 

 dissociation in homogeneous flames. It related to the chemical com- 

 position and the distribution of heat in a flame produced by a mixture 

 of oxygen and hydrogen, or carbonic oxide and oxygen burnt from an 

 oxy-hydrogen blow-pipe. The author in this paper describes the re- 

 sults with carbonic oxide and oxygen, mixed in the proportion to form 

 carbonic acid. The flame is seen to be composed of an outer and 

 inner cone ; the latter composed of the uncombined gases, the former 

 of the gases in combustion. The interior cone had a height of about 

 10 millimetres, while the more visible part of the exterior cone rose to 

 70 or 100 millimetres. 



The observations show, — 



1. That the temperature goes on increasing from the lower part of 

 the flame up to the summit of the interior cone. 



2. That the proportion of uncombined gases (oxygen and car- 

 bonic oxide) to the combined gas (carbonic acid) increases from tho 

 upper part of the dart of flame, where carbonic acid alone was found, 

 down to the lower part (summit of interior cone) where only two-thirds 

 of the oxygen and carbonic oxide had united. 



M. Tresca, whose experiments of the flow of solid bodies (soft 

 metals and ceramic pastes) from a small aperture when submitted to 

 great pressure, are known to our readers, has now extended his re- 

 searches to ice. This body is found to issue in exactly the same way 

 as the solids above mentioned. The jet is formed of perfectly distinct 

 concentric tubes, which, however, in this case are grooved through 

 their entire length with transverse fissures which gave to the jet the 

 appearance of being made up of washers arranged one after another. 

 The results support strongly Dr. Tyndall's theory of constitution of 

 glaciers. Some effects resembling moraines were, indeed, seen when 

 coloured ice was employed in the experiments. 



At one of the recent meetings of the French Academy of Sciences, 

 M. de Verguette Lamotte made a communication on the effects of heat 

 in the preservation and improvement of wines. Burgundy is well 

 known to be much improved by a voyage to and from Calcutta. This 

 fact led the author to try the effects of warmth on wines at home, and 

 both he and M. Pasteur have coace to the conclusion that wines may 

 be mtich improved by gently warming them, and that sick wines may 

 be cured by the same means. M. Pasteur has, in fact, taken out a 

 patent for warming wines by placing the bottles in a hot-air stove with 

 the corks tied down to prevent their being forced out by the expan- 

 sion. The bottles must be quite full, and have no air in them, and are 

 heated to 64° C. for half-an-hour, after which the cork is untied, 

 driven home, and sealed down. In the process just described of 



