The Annual of Scientific Discovery, (published in Boston by Gould and Lincoln), is an excellent abstract of all the chief movements and discoveries in the scientific world for the year 1850. We advise all our readers interested in any of the sciences to procure it, and its companion volume for the previous year. The work will be continued, and it will be invaluable as a library of facts and suggestions.
Oxygen from Atmospheric Air.—M. Boussingault has recently obtained some interesting results from his investigations in relation to oxygen. The problem upon which he has been engaged was the extraction of oxygen gas, in a state of purity and in a considerable quantity, from the azote in the atmosphere. For this purpose, a preference was given to baryte, owing to its property of remaining in oxygen of a moderate temperature, and abandoning it under the influence of a heat sufficiently intense. Ten kilogrammes of baryte, completely oxidized, were found able to take and afterward return 730 litres of gas. This is the number indicated by theory; for celerity of operation, more than 600 litres can be counted on. In that limit, and in operating on 100 kilos. of matter, 6,000 litres of oxygen gas might be disengaged at each disoxidization; four or five operations might be performed in 24 hours, which would thus furnish from 24,000 to 30,000 litres of gas.
The discovery of the virtues of a Whitened Camera for Photography, announced in our last issue, has excited a remarkable sensation in England. Mr. Kilburn, photographer to the Queen, who has experimented upon the new plan with great success, is sparring with M. Claudet. The point in dispute is the tendency of the improved method to weaken the image. If the statements of those who claim to have succeeded are reliable, it is evident that the ordinary form of camera may be abandoned, and any image be received directly from the lens upon plates or paper exposed to a diffused light.
M. Laborde states, in a paper on Photography read before the Paris Society for the Encouragement of Arts, that the nitrate of zinc may be substituted for acetic acid in the preparation of photographs on paper; that it increases the sensitiveness of the silver coating, and even allows an alkaline reaction to the iodide of potassium bath.
A paper was lately read by Professor Abich, before the Geographical Society of London, on the Climate of the Country between the Black and Caspian Seas. Professor Abich noticed the outlines of the extraordinary variety of climate in the lands between these bodies of water, and sketched the geological and orological structure of the country, which he has minutely examined for several years by order of the Russian Government. The whole tract is divided by three different lines of elevation—viz. that of S. E. to N. W.—that of W. to E., and that of S. W. to N. E. The isothermal line of 57° and 59°, after traversing the country between the Black and the Caspian Seas, inflects abruptly toward the South again, reaching the Caspian. The mean temperature along the shores of the two seas is for the year about equal; but the difference of the temperature of the seasons is very great. Lenkoran, in the same latitude as Palermo and Smyrna, with an annual temperature of 61° and 63°, has the summer of Montpellier 76°, and the winter of Maestricht and Turin, 35°. In Calchis, there is the winter of the British Isles, 41° and 42°, and the summer of Constantinople, 72° and 73°. Tiflis, with the winter of Padua, 37°, has the summer of Madrid and Naples, 74°. The extremes of Asiatic climate are found on the volcanic highlands of Armenia.