4042. To Obtain Hydrogen Gas

4042.     To Obtain Hydrogen Gas. Hydrogen gas is readily procured by pouring on fragments of zinc, in a glass bottle, or flask with a bent tube, or retort, some diluted sulphuric acid ( 1 measure of strong acid to 5 of water). It may be collected over water. If zinc be not at hand, fine iron wire, or the turnings or filings of iron, may be substituted for it. To procure gas of great purity, distilled zinc must be used, and it is advisable to pass the gas first through alcohol, and then through a concentrated solution of pure po-tassa. Care must be taken that all the air has been driven out of each vessel before any light is applied, or an explosion will ensue.

4043. Cheap Method of Obtaining Hydrogen

4043.    Cheap Method of Obtaining Hydrogen. Take quicklime, slack it, let it cool and crumble into a dry hydrate; then mix it with charcoal, coke, or peat, and heat in a retort. The hydrate of lime (slacked lime) gives up the water that was used in slacking it, and becomes quicklime. The water is decomposed into hydrogen and carbonic acid, and these two gases can be separated by passing them through water, or the carbonic acid may be economized by employing it in the manufacture of bicarbonates. The quicklime can be again slacked and used as often as required.

4044. Hydrogen Gas for Balloons

4044.     Hydrogen Gas for Balloons. For this purpose hydrogen may be obtained by pouring slightly diluted muriatic acid upon an equal weight of zinc, in a covered vessel having a small tap or stop-cock in the top for filling the balloons. The vessel should be made of lead, to prevent corrosion.

4045. To Estimate the Buoyant Power of Balloons

4045.    To Estimate the Buoyant Power of Balloons. It will take about 12 cubic feet of the hydrogen gas, used for inflating balloons to balance or suspend 1 pound in the air. The rule used for balloons is as follows: The specific gravity of the gas compared with the air is .0693; 1 cubic foot of air weighs 527.04 grains, the cubic foot of gas weighs 36.93 grains; and therefore there are 527.04-36.93=490.11 grains difference between the air and gas, in one cubic foot. Multiply this difference by the number of cubic feet in the balloon, and divide by 7,000. This will give the capacity or buoyancy of the balloon, in pounds; then subtract the weight of the balloon and car.

4046. For Obtaining Hydrogen in Quantities

4046.     For Obtaining Hydrogen in Quantities. Place iron wire in a gun-barrel, or a porcelain tube, open at both ends, to one of which attach a retort containing water, and to the other a bent tube, connected with a pneumatic trough. The gun-barrel must now be heated to redness, and the water in the retort brought into a state of brisk ebullition, when the vapor will be decomposed, the oxygen being absorbed by the iron, and the hydrogen escaping into the gas receiver. The gas evolved may be purified, if desired, by passing it through alcohol, etc.. (See No. 4042 (To Obtain Hydrogen Gas).)