an equal volume of sulphuric acid of the density of 1.53, the color ought not to become darker, but lighter. A petroleum that satisfies all these conditions, and possesses the proper flashing-point, may be regarded as pure and safe.
The Paris Academy of Sciences has elected Mr. Darwin a corresponding member of the Zoölogical Section, and Prof. Asa Gray a corresponding member of the Section of Botany.
We have received from Dr. G. E. Blackham, of Dunkirk, a report of what was done at the American Microscopical Congress, which met at Indianapolis in August. There were present about fifty microscopists from different parts of the United States, and Dr. R. H. Ward, of Troy, New York, was chosen president. The congress was in session for four days, August 14th, 15th, 16th, and 17th, and one of its results was the organization of a permanent association, "The American Society of Microscopists." A large number of papers were read, among which may be named the following: "On the Limits of Accuracy in Measurement with the Microscope," by Prof. W. A. Rogers; "A Standard Micrometer," by Prof. R. Hitchcock; "Progress of Microscopic Ruling," by Prof. J. E. Smith; and "Construction of Oculars," by W. H. Seaman. The society will meet next year at Buffalo.
Prof. Hughes entertains the hope, or rather thinks it possible, that we shall one day be able to "tap the brain of its thought" by means of the microphone! He holds that all thought is accompanied by an unconscious action of the articulating organs, and that therefore it may come to pass that by a highly-sensitive microphone the articulate vibrations of the head will be made audible. Of course, the theory that unconscious articulation always accompanies thought is purely hypothetical; but in these times it is best not to pronounce anything impossible unless it clearly implies a contradiction in terms—an absurdity.
Experiments made by Messrs. Corenwinder and Contamine show that the amount of sugar in beet-roots is in direct ratio to the superficial area of their leaves. They further show that in the leaves the sugar occurs mainly in the midrib, and that it there exists in the state of glucose mingled with a small quantity of crystallizable sugar. In the secondary veins and in the parenchyma the proportion of sugar is far less considerable.
The London Academy is authority for the statement that Mr. Grenville Murray's recent work, "Round about France," has been seized in France by the authorities.
Dr. Weyl points out in the Chemische Industrie the defects of the usual methods of determining the heat-value of fuels, and recommends, as preferable, decomposition of the fuel by dry distillation and analytical determination of the solid, liquid, and gaseous products of decomposition. The water, tar, and gas that are formed are measured and their heat of combustion ascertained with the aid of data that have been supplied by Favre and Silbermann and Deville. The final result will, of course, exceed the true combustion-value of the coal by the amount of heat equivalent to the work of decomposition into coke, tar, and gas. The decomposition of the coal should be done as quickly as possible, and at a high temperature.
The French journal La Science pour Tous reckons the annual importation of ivory into England at 650,000 kilogrammes, of which about one half is there employed in the arts, and the other half reëxported. The cutlery-works of Sheffield alone consume 200,000 kilogrammes per year. Tusks vary in weight from 450 grammes to 74 kilogrammes. To supply the ivory annually taken to England, 50,000 elephants must be killed. But though, perhaps, most of the tusks go to England, very many are exported directly to other countries and consumed at home.
A process for treating hop-stems so as to produce from them textile fibres is thus described in the Polytechnic Journal: First, the stems are boiled in water with soda or soap, then washed again, and once more boiled in dilute acetic acid. They are then washed and dried, and when properly combed can be worked like other textile materials. The fibres are said very closely to resemble those of flax, and to excel in elasticity, softness, and durability.
A writer in the London Times asserts that, by the practice of shoeing horses, we diminish the sureness of the animal's feet, and foster all kinds of splints and other diseases. He maintains that any horse, even one accustomed to shoes, would very soon go more easily in every way on our hardest roads, and with far less liability to slipping and disease, unshod, than he now does when shod with iron. All that is necessary is to "keep the edges of the hoof slightly rounded off with a rasp, to prevent the raveling-up of the edges."
Señor Moreno, employed by the Government of Buenos Ayres to explore Patagonia, has discovered a new volcano, that of Chalten, in the Patagonian Andes, in latitude 49° 8' south, longitude 73° 10' west. It is a magnificent peak, rising high above the surrounding mountains, and the natives report that it is almost always sending forth smoke and cinders.
