Chemical Lecture Experiments; Non-Metallic Elements (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1905 Excerpt: ...a lighted taper is applied to the cylinder; the gas will have become so far replaced by air that the combustion will be attended with the characteristic sound produced by combustion of mixtures of air and hydrogen. It may be compared with the effect produced by igniting hydrogen in a, similar cylinder which has been filled with the gas. The length of time necessary to insure a detonating mixture of air and hydrogen must be determined by previous trial. A cylinder 30 millimetres diameter and 12 centimetres long must be allowed from 2 to 3 minutes. 351. To show the escape of hydrogen through a cracked flask. A flask having a minute crack in it is fitted with a cork carrying a straight piece of small bore tube about 20 centimetres long. The flask is filled with hydrogen by displacement, the cork inserted, and the apparatus inverted and supported in a clamp so as to dip the open end of the tube into a small beaker of coloured water. As the hydrogen diffuses through the crack the coloured liauid will be seen to rise in the narrow tube. The x flask for this experiment may be cracked by touching it at one spot near the bottom with the point of a hot piece of glass, and then quickly touching the same spot with a moistened finger; this usually results in the production of a short crooked crack. It may be necessary to crack two or three flasks before one is obtained that is satisfactory, but when one is so secured it should be carefully preserved; it is well to keep it under a glass bell-jar in order to prevent its getting dirty, as it should on no account be washed. 352. To show the diffusion of gases into each other through a long tube. Two soda-water bottles are connected together by a piece of combustion tube about 60 centimetres long, the tube being fitted to th...