These results are fully confirmed by the results which were obtained by Franz Schulze, in Rostock, in 1868, 1869, 1870, and 1871. The averages which he got, with very small variation, were 2.8668 for 1869, 2.9052 for 1870, and 3.0126 for 1871.
More recently Muentz and Aubin have analyzed air collected on the plains near Paris, on the Pic du Midi, and on the top of Puy-de-Dome. Their results agree with those published by Reiset and Schulze.
The grand average of carbonic oxide in the air seems to be tolerably fixed, but after this starting-point is established it remains to study the variations that it is capable of, not from local causes, which are of little importance, but from general causes connected with large movements of the air. Upon this study, which demands the co-operation of a definite number of observers stationed at different and distant points of the earth, the experiments being made simultaneously and by comparable methods.
M. Dumas called the attention of the Academy to this point, in connection with its mission of selecting suitable stations for observing the transit of Venus. The process and apparatus of Muentz and Aubin offer the means adapted for making these experiments, and seem sufficient to solve the problem which science proposes, of determining the present quantity of carbonic acid in the air.
If these experiments yield satisfactory results, as we have good reasons to believe they will, it is to be hoped that annual observations will be made in properly-chosen places, so as to determine the variations which may possibly take place in the relative quantity of atmospheric carbonic acid during the coming century.--Compt. Rend., p. 589.
[Although this proposition was made by a Frenchman to his fellow scientists, would it not be well for some American to accept the challenge, and bring it before the coming meeting of the American Association for the Advancement of Science, in the hope that we, too, may contribute our mite of effort in the same direction?--Ed. Knowledge.]
THE INFLUENCE OF AQUEOUS VAPOR ON THE EXPLOSION OF CARBONIC OXIDE AND OXYGEN.
[Footnote: Read before the British Association, Southampton Meeting, Section B, 1882.]