Page:Popular Science Monthly Volume 21.djvu/733

Rh It is not necessary to insist upon the contrast thus afforded between this method of administration and the one that has hitherto been used, in which the operator, making his patient breathe dense chloroform directly into his nostrils, has to exercise the greatest caution lest he kill him. The manageable zone of ether is a little more than three times as wide as that of chloroform, while that of the protoxide of nitrogen is considerably wider than that of ether. Here we see why ether is less, and the protoxide of nitrogen still less, dangerous than chloroform. M. Bert's researches further show that it is not so much the absolute quantity of the anæsthetic that should be regarded as the proportion in which it is mixed with air. A dog can safely be made to absorb many times as much chloroform as would kill him, if it were pure, provided it is so diluted as to bring its strength within the manageable zone.

Poisonous Food-Colors.—The prefect of police of Paris has expressly forbidden the use of any of the following substances in coloring sweetmeats, liquors, and foods: Mineral Colors.—The compounds of copper—blue verdigris, mountain blue. Compounds of lead—oxides of lead—massicot and minium. Oxychloride of lead—Cassel yellow, Turkey yellow, Paris yellow. Carbonate of lead—white-lead, flake-white. Antimoniate of lead—Naples yellow. Sulphate of lead. Chromates of lead—chrome yellow, Cologne yellow. Chromate of baryta—yellow ultramarine. Compounds of arsenic—arsenite of copper, Scheele's green, Schweinfurth green. Sulphide of mercury—vermilion. Organic Colors.—Gamboge and Naples aconite. Fuchsine and its sub-products, such as Lyons blue. Eosine. Nitro-derivatives, such as naphtol yellow and Victoria yellow. The use of these substances in coloring wrapping-papers for any kind of food is prohibited, and manufacturers and dealers will be held responsible for any accidents that may occur through disobedience of the prefect's order.

The Meteorograph.—Messrs. Van Rysselberghe and Schubert exhibited at the Paris Exposition of Electricity an instrument they called a meteorograph, for representing by means of continuous curves drawn automatically upon a sheet of zinc all the principal atmospheric variations, the knowledge of which is indispensable in meteorological investigations and in making forecasts of the weather. M. Theorell, of Stockholm, exhibited another machine, of a more complicated character, which indicates, by printed figures in six columns on an endless roll of paper, the hour when the observation is taken, the velocity of the wind, its direction, the indications of the wet and of the dry thermometer, and the indications of the barometer. Notwithstanding the complicated character of the machinery that must do so much, the instrument has borne admirably the test of use at the University of Upsala, where it has been employed for two years in registering the condition of the atmosphere every quarter of an hour. For immediate use in the observatory it is not as convenient as the Rysselberghe instrument, the graphic curves of which can be read off and appreciated at sight; but it is much its superior for use in cases where the facts have to be transmitted by telegraph.

Sea Telegraphy for Ships.—M. Menusier has proposed a plan of telegraphy for the use of ships at sea. Upon his cable, which he would lay from the French coast to New York, with a branch to Panama, he proposes to ingraft at distances of about one hundred and eighty miles, representing a ship's daily sailing distance, vertical cables rising to the surface where the ends may be held up by buoys. To the main cable he would also add secondary cables thirty or sixty miles long, forming cross-cables, like great arms stretching out on either side, to which other vertical cables would be attached, each to be held in place by its surface buoy. Thus it could rarely happen that a ship keeping on the regular course would not be able to meet one of the buoys every day. Each buoy should have its number and its place marked on a special chart. If a ship wishes to send a dispatch, it attaches the wires of its, own telegraphic apparatus, one to the cable that is held up by the buoy, the other to the buoy itself, which is of course in communication with the earth-currents. M. Menusier professes to solve the principal difficulty in the way of the successful