PROFESSOR KOPP ON April 15 1850. THE PRESIDENT (Richard Phillips Esq.) in the Chair. Joseph Danson Esq. Edward S. Tudor Esq. and Alfred Anderson Esq. were elected Fellows of the Society. The following presents were announced cc Journal of the Franklin Institute :” from the Institute. “On the Diffusion of Liquids,” by Professor Graham from the Author. The following papers were read XILI.-On the Relations between the Chemical Composition and the Boiling Points and Xpecijc Volumes. By PROFESSOR KOPP. HERMANN I had formerly established the fact that with analogous coin-pounds a difference of C H in their composition corresponded to a constant difference of about 19O in their boiling points and likewise to a constant difference in their specific volumes.I determined the latter finally* to be about 21.8 for the boiling points of the substances in question ;e.g. the specific volume of alcohol being 58.5 that of methyl-alcohol was found to be 38.6 difference 199.-Dr. Miller+ has since made use of Pierre’s observations to put these statements to the test and bclieves himself warranted in concluding that they are contradictory to facts because the numbers obtained by Pierre’s observations which according to the above statements * Ann. Ch Phaim. L 21. t Chem. SOC. Qu. J. I 363. BOILING POINTS AND SPECIFIC VOLUMES. 105 should be constant are found in reality to exhibit too many discrepancies. I cannot believe this conclusion to be correct. The results of Pierre have been contradicted in part and I believe corrected by some researches conducted by myself with the greatest possible care.* The following table shows a comparison of the numbers arrived at by the observations of Pierre and myself for the boiling points and specific volumes rhe difference C H in br the boiling the specific points.volume. ?ierre KOPP. ?ierre Alcohol and methyl-alcohol . . . . 120.0 12O-9 19 -3 19 09 Iodide of ethyl and iodide of methyl . . . . . 26 *2 -17 a5 -c_ Bromide of ethyl and bromide of methyl . . . . 27 -7 -20 -0 Acetate of oxide of ethyl and acetate of oxide of methyl . 15 -6 18 *O 14 *7 23 -6 Butyrate of oxide of ethyl and butyrate of oxide of methyl. 16 -9 18 *9 36 9 23 *5 Acetate of oxide of ethyl and formiate of oxide of ethyl .21 *2 19 *4 20 -0 22 *7 Acetate of oxide of ethyl and butyrate of oxide of methyl . 27 09 21 *6 7 *o 18 *8 Butyrate of oxide of ethyl and acetate of oxide of ethyl . 17 *4 20 *2 13 *5 21 -1 Butyrate of oxide of methyl and acetate of oxide of methyl. 21 03 19 *8 10 4 21 -2 Butyrate of oxide of methyl and formiate of oxide of ethyl. 24 -6 20 *5 13 -1 20 *8 Butyrate of oxide of ethyl and formiate of oxide of ethjl 22 so 20 *o 21 -0 21 07 Butyrate of oxide of ethyl and acetate of oxide of methyl . 19 *8 19 *5 19 03 22 *o Hydrated oxide of amyl and alcohol. . . . . 17 *8 17 *6 20.3 20 *3 Hydrated oxide of amyl and methyl-alcohol . . . 16 03 16 *4 20 -1 30 *2 It will be seen from the above that many of the numbers which were found by Pierre's researches and exhibit the greatest dis- crepancies from my statements are very different from those arrived at by my determinations which agree very nearly with the laws. The existence of ai kind of law cannot be denied even if the numbers which should be constant are found by experiment to exhibit discre- pancies. * Pogg. Ann. LXXII 223.