CHEMICAL SCIENCE. 



283 



least speculate that the three may form a series consisting of tv, r o substances 

 combined in different proportions. It is true that wo must lie extremely 

 cautious ahotit venturing upon hypotheses involving a compound constitu- 

 tion of bodies which all our efforts have hitherto proved ineffectual to de- 

 compose; but, on the other hand, it must be admitted, that when we had 

 so-called elements arranging themselves into a series of terms having a 

 common difference, and when we find the terms of these series united by 

 equality or simple relation of atomic volume, we cannot grant that their 

 elementary nature has been absolutely established. 



The following substances combine relations of chemical equivalents already 

 pointed out, with analogies of atomic volume : 



(Where phosphorus, arsenic, etc., are compared in the solid state, the 

 unit of relation is of course different.) It has been already remarked, that, 

 in point of chemical relations generally, lead and tin are less closely united 

 with the series than the other members composing it ; but the relation be- 

 tween the atomic volumes of lead and antimony the latter almost the last 

 term at the other end of the series is almost absolutely exact. Nitrogen 

 is of course omitted in the second table, as we do not know what would be 

 its atomic volume in the solid state. 



For the further details of this paper, we must refer our readers to the 

 journal to which they were originally contributed. In conclusion, however, 

 Mr. Lea remarks, that the relation developed by him, depending upon the 

 same, or approximately the same number, extends to no less than forty-eight 

 of the elementary bodies, the differences rarely exceeding the possible er- 

 rors in the determination of the chemical equivalents; or to all the elements 

 except those as yet imperfectly understood, most of which may yet range 

 themselves under the same law, and except the oxygen group, oxyjren, sul- 

 phur, selenium and tellurium, substances which stand alone and unmistak- 

 ably apart from the other elements. 



* The numbers here given for the atomic volumes are calculated from the specific 

 gravities adopted in G mean's Handbook, aud the latest and most reliable deter- 

 minations of chemical equivalent. 



