316 Miscellaneous Intelligence. 



dential address of Lord Francis Egerton at the meeting in Man- 

 chester of 1842, and referred then to Jonle, another Manchester 

 philosopher, as the worthy successor of Dalton. Sir Henry then 

 proceeded to consider " what light the research of the past fifty 

 years has thrown on the subject of the Daltonian atoms : First, 

 as regards their size ; secondly, in respect to their indivisibility 

 and mutual relationship ; and thirdly, as regards their motions." 



As to the size of atoms, Dalton believed them immeasurably 

 small ; but, in 1865, Loschmidt, of Vienna, reached the conclusion 

 that the diameter of an atom of oxygen or nitrogen was 1/10,000,000 

 of a centimeter, and a few years later, William Thomson demon- 

 strated that the distance between the centers of contiguous mole- 

 cules is less than 1/5,000,000, and greater than 1/1,000,000,000 of a 

 centimeter. As regards atomic weights, and the idea of hydrogen 

 as a unit, conclusions of Dalton and Prout, the present position of 

 science is that the weights in many instances are not exact multi- 

 ples of hydrogen ; and yet they are so near that " we are con- 

 strained to believe that the approximations cannot be a mere mat- 

 ter of chance ; that there is a reason for it which science will 

 yet discover." Xew relations between groups of elements also 

 have been ascertained, as that which, through Mendelejeff, has 

 proved to be prophetic of new discoveries of elements, and which 

 has appeared to point to the conclusion that the elements have 

 been derived from a common source. The indivisibility of atoms, 

 assumed to be a fact by Dalton, has hence become a subject for 

 investigation and argument. But actual division has not yet 

 been accomplished by the highest terrestrial temperatures, that of 

 the electric spark ; nor has it been proved by the study of the 

 sun's conditions, nor by the investigations of the spectra of the 

 fixed stars ; so that the idea of evolution of the elements is not 

 yet proved. On this important point we cite here the words of 

 the address. 



"How far, now, has this process of simplification been carried ? 

 Have the atoms of our present elements been made to yield ? To 

 this a negative answer must undoubtedly be given, for even the 

 highest of terrestrial temperatures, that of the electric spark, has 

 failed to shake any one of these atoms in two. That this is the 

 case has been shown by the results with which spectrum analysis, 

 that new and fascinating branch of science, has enriched our 

 knowledge, for that spectrum analysis does give us most valuable 

 aid in determining the varying molecular conditions of matter is 

 admitted by all. Let us see how this bears on the question of 

 the decomposition of the elements, and let us suppose for a mo- 

 ment that certain of our present elements, instead of being distinct 

 substances, were made up of common ingredients, and that these 

 compound elements, if I may be allowed to use so incongruous a 

 term, are split up at the temperature of the electric spark into 

 less complicated molecules. Then the spectroscopic examination 

 of such a body must indicate the existence of these common ingre- 

 dients by the appearance in the spark-spectra of these elements of 



