Professor Marangoni, of Pavia, has invented an aspirator for measuring gases which is much simpler than many now in use in laboratories, which latter have the defect that the air or gas ascends through the descending liquid and makes thus the measuring of the former uncertain. The improved apparatus is shown in our illustration. It consists of two vessels attached to a fixed horizontal shaft, FE, which is placed upon two upright supports. This shaft has several ways or passages made in it which performs the functions of the taps. The water of the upper receptacle passes into the lower one by the passage, A, and thence through the tube, BC, issuing at its lowest extremity at C. The air contained in the lower vessel is thus emitted by the channel DE, cut into the shaft, while the air or gas is aspirated in the same ratio by the passage and tube, FG. The apparatus acts thus at the same time as aspirator and compressor. It is simple, and will be a useful addition to the laboratory. [Illustration] * * * * * NEW PHOTOGLYPTIC PROCESS.[1] [Footnote 1: A communication to the Photographic Society of France.] WALTER B. WOODBURY. It is now thirteen years since I had the honor of introducing in France my new photoglyptic process, which, up to the present time, has remained in the hands of very few, owing to the great expense hitherto necessary to start the working of it. For some time I have been engaged in making experiments with a view to discover a system which should be at the same time simple and inexpensive; and the process which I have this evening the honor to bring before your notice is the result of my researches. The summary of the new system is as follows: To obtain from negatives reliefs on glass similar to transparencies by the carbon process, but modified in the quantity of materials used. To attach, and keep in absolute contact with the relief so obtained, a sheet of tin foil. To solidify this sheet of tinfoil by coating it with copper; then backing it up with another sheet of plate glass covered with a composition; and then to detach the whole from the first relief--the result being a mould ready to place in the press and print one thousand or more proofs. I commence by showing you the relief made from the negative, and explaining how this is obtained. I take a sheet of plate glass of a convenient size, and place it in hot water, together with a sheet of paper a little smaller; then, having driven out the excess of water by means of a squeegee, I place it on a leveling stand. Having prepared a solution composed of gelatine 200 parts, water 1,000 parts, glycerine 20 parts, white sugar 30 parts, with a little Indian ink, and filtered the same, I pour a sufficient quantity on the paper and spread it up to the corners with the finger. These plates are then dried in a dry place and can be kept until wanted.