British Association for the Advancement of Science. 115 



fiant gas, by the abstraction of more and more hydrogen, and the 

 substitution of a corresponding quantity of chlorine, till the whole 

 four atoms of hydrogen of the olefiant gas are replaced by chlo- 

 rine. This view, which represents the protochloride of carbon as 

 consisting of four atoms of carbon and four of chlorine ; or ole- 

 fiant gas with its hydrogen replaced by chlorine, is consistent 

 with the observed density of its vapor. Olefiant gas, also, has 

 the four atoms of carbon belonging to alcohol from which it was 

 formed, so that the protochloride of carbon has the carbon of 

 alcohol from which it was primarily derived, and thus preserves, 

 after numerous mutations, the most distinct traces of its origin. 

 2. The binary theory of the cotistitution of bodies, advocated by 

 Liebig. This is the theoretical resolution of bodies, apparently 

 the most complex, into not more than two proximate constituents, 

 one of which, also, is generally a simple substance. There can 

 be no doubt that compound radicals will be the basis of the clas- 

 sification of organic compounds, and that thus the same sim- 

 plicity of arrangement will be introduced into organic compounds, 

 as now exists in the metallic combinations of inorganic chemistry. 

 A communication was read from Prof. Hare, of Philadelphia, 

 on the preparation of barium, strontium and calcium. By means 

 of the alternate action of two deflagrators, each of 100 pairs, 

 containing more than 100 square inches of zinc surface, assisted 

 by refrigeration. Dr. H. has procured amalgams of these metals 

 from their chlorides, and by distillation in an iron crucible, in- 

 cluded in an air-tight alembic of the same metal, has extricated 

 them from their mercurial solvent. (For full details, see this 

 Journal, vol. xxxvii, p. 267.) 



Mr. Coathupe, of Bristol, described an improved method of 

 graduating glass tubes for eudiometrical purposes; and also ex- 

 hibited an apparatus for determining the amount of carbonic acid 

 in the atmosphere. 



The Baron Eugene Du Mesnil gave a description of a safety 

 lamp invented by him in 1834. It consists of a body of flint- 

 glass, defended by a dozen of iron bars. The air is admitted by 

 two conical tubes, inserted at the bottom, which are capped with 

 wire-gauze, and enter by the side of the flame. The latter rises 

 into a chimney, which has a piece of metal placed in the form of 

 an arch over its top ; the chimney being quite open. In conse- 

 quence of this construction, a strong current is constantly passing 



