INVESTIGATION OF TEMPERATUEE CHANGES. 227 



the observers, Avhich is not the case as respects the observations taken under 

 the direction or supervision of the Smithsonian Institution. 



E. Plantamour has published, in several elaborate papers, the results of 

 the working up of the meteorological observations made at Geneva, in 

 Switzerland.* These papers, to Avhich we shall have occasion to refer again, 

 are most admirable specimens of critical and scientific ability in the hand- 

 ling of a mass of material, of the probable accuracy of which we are justified 

 in having a high opinion. This opinion is based in part on the fact that 

 Plantamour himself does not feel authorized to accept the observations made 

 previous to the year 1826 as being accui-ate enough for use in an investiga- 

 tion of the kind proposed. The series therefore is a short one, embracing 

 a period of only fifty years, or from 1826 to 1875, but its value is unques- 

 tionably greater than it would have been had the results of the earlier 

 inaccurate observations been embraced in the investigations. So far as the 

 question of a secular change of the temperature is concerned, no definite 

 result appears to have been reached b}' Plantamour. The addition of the 

 observations of the ten j'ears 1865-1875 to the series 1826-1865 gave a 

 mean one-tenth of a degree (centigrade) higher than obtained for the latter 

 series b}' itself; but this difference is too small to be considered as furnishing 

 positive testimonj' on the point in question. 



Similar negative results in reference to proofs of secular change of tem- 

 perature seem to have been obtained by other meteorologists in Europe, 

 notably by Dove and Quetelet ; at least the writer has not been able to find 

 anything in their numerous publications on climate to justify the conclusion 

 that positive proofs of any increase or diminution of the temperature had 

 been afforded by the observations worked up by either of these eminent 

 specialists in this branch of scientific inquiry. 



The only investigations which seem to lead to a positive result are those 

 of Glaisher ; and as this has been repeatedly quoted and much commented 

 on, a more detailed reference may here properly be made to it, although, for 

 reasons which will be given, the present writer places no confidence in the 

 conclusions drawn by that author. Mr. Glaisher's results may be thus con- 

 cisely stated. The fifty years which elapsed between 1813 and 1863 being 



* Professor Plantamour's papers will be found in the Memoires de la Societe de Physique et d'Histoire Natu- 

 relle de Geneve, Tomes XIII., XIV., XIX. (p. 201), and Tome XXIV. (j.. 397). The latter is by far the most 

 elaborate invebtigation of all, and embraces the whole series of observations from 1826 to 1875. Consult also "Du 

 Climat de Geneve," a separate work by the same author, published at Geneva in 1863. 



