CHEMICAL SCIENCE. 167 



of 200 a minute, would require all the inhabitants of the globe, suppos- 

 ing them to be a thousand millions, to count incessantly for 19,025,875 

 years, or for more than 3000 times the period for -which the human race 

 has been supposed to be in existence. Low's Inquiry into the Simple 

 Bodies of Chemistry. 



OBSERVATIONS ON ATOMIC VOLUMES, WITH CONSIDERATIONS ON THE 

 PROBABILITY THAT CERTAIN BODIES NOW CONSIDERED AS ELEMENT- 

 ARY MAY BE DECOMPOSED. 



PROF. DUMAS, at the British Association, alluded to the solubility of 

 some substances, and the insolubility of others, giving many instances 

 of the difference of this quality in regard to solution in water, sul- 

 phuric and strong acids, and referred to Berthollet's views and experi- 

 ments on this subject. The measure of volume of bodies, he thought, 

 might be represented with as much facility as the weight ; thus, for 

 example, magnesia and sulphuric acid may have their volumes numer- 

 ically expressed before and after combination, and also graphically by 

 lines. Magnesia with sulphuric acid showed a certain degree of con- 

 densation, lime a greater condensation, and barytes the greatest con- 

 densation ; and these he could represent and reason on as well by lines 

 of different lengths as by figures or by words. The degree of condensa- 

 tion had also relation to the quality or degree of solubility. Thus, 

 sulphate of magnesia was very soluble, sulphate of lime but little solu- 

 ble, and the greatly condensed sulphate of barytes was insoluble. He 

 then pursued the analogy with the chlorides, comparing the chloride 

 of sodium with the extreme case of the chloride of silver. After graph- 

 ically expressing the solubility of bases with sulphuric acid by lines, 

 he proceeded to show that the relative volumes of the elements chlo- 

 rine, bromine, and iodine, could be perfectly represented by lines equal 

 in length. Prof. Dumas said that when a number of metals are repre- 

 sented by lines, at first they seem in confusion, and it would appear 

 like an impossibility to arrange them in a system of lines, to permit 

 their relations to appear ; but when considered in relation to the sub- 

 stitution of one property for another, or of the substitution of one sub- 

 stance for another in groups, then their arrangement became easy. 

 Many examples were given of groups of bodies such as the alkalies, 

 earths, &c., arranged in the order of their affinities. He also called 

 attention, in the Triad groups, to the intermediate body, having most 

 of its qualities intermediate with the properties of the extremes, and 

 also that the atomic or combining number was also of the middle term, 

 exactly hah of the extremes added together ; thus, sulphur 16, sele- 

 nium 40, and tellurium 64. Half of the extremes give 40, the number 

 for the middle term. Chlorine 35, bromine 80, and iodine 125. Of 

 the alkalies, lithia, soda and potassa, or earths, lime,_ strontia and 

 baryta, afforded, with many others, examples of this coincidence ; hence 

 this suggestion, that, in a series of bodies, if the extremes were known 

 by some law, intermediate bodies might be discovered ; and, in the 

 spirit of these remarks, if bodies are to be transformed or decomposed 

 into others, the suggestion of suspicion is thrown upon the possibility 



