94 Mr. Faraday on the [Feb. 



Sulphuretted Hydrogen. 



A tube being bent, and sealed at the shorter end, strong 

 muriatic acid was poured in through a small funnel, so as nearly 

 to fill the short leg without soiling the long one. A piece of 

 platinum foil was then crumpled up and pushed in, and upon 

 that were put fragments of sulphuret of iron, until the tube was 

 nearly full. In this way action was prevented until the tube 

 was sealed. If it once commences, it is almost impossible to 

 close the tube in a manner sufficiently strong, because of the 

 pressing out of the gas. When closed, the muriatic acid was 

 made to run on to the sulphuret of iron, and then left for a day 

 or two. At the end of that time, much protomuriate of iron had 

 formed, and on placing the clean end of the tube in a mixture of 

 ice and salt, warming the other end if necessary by a little water, 

 sulphuretted hydrogen in the liquid state distilled over. 



The liquid sulphuretted hydrogen was colourless, limpid, and 

 excessively fluid. Ether, when compared with it in similar 

 tubes, appeared tenacious and oily. It did not mix with the 

 rest of the fluid in the tube, which was no doubt saturated, but 

 remained standing on it. When a tube containing it was opened, 

 the liquid immediately rushed into vapour ; and this being done 

 under water, and the vapour collected and examined, it proved 

 to be sulphuretted hydrogen gas. As the temperature of a tube 

 containing some of it rose from 0° to 45°, part of the fluid rose 

 in vapour, and its bulk, diminished ; but there was no other 

 change : it did not seem more adhesive at 0° than at 45°. Its 

 refractive power appeared to be rather greater than that of 

 water ; it decidedly surpassed that of sulphurous acid. A small 

 gage being introduced into a tube in which liquid sulphuretted 

 hydrogen was afterwards produced, it was found that the pres- 

 sure of its vapour was nearly equal to 17 atmospheres at the 

 temperature of 50°. 



The gages used were made by drawing out some tubes at the 

 blowpipe table until they were capillary, and of a trumpet form ; 

 they were graduated by bringing a small portion of mercury 

 successively into their different parts ; they were then sealed at 

 the fine end, and a portion of mercury placed in the broad end ; 

 and in this state they were placed in the tubes, so that none of 

 the substances used, or produced, could get to the mercury, or 



tuies of these, and when any one was found of the same specific gravity as the fluid in 

 which it was immersed, the specific gravity of the fluid was taken : thus a number of 

 hydrometrical bulbs were obtained ; these were introduced into the tubes in which the 

 substances were to be liberated ; and ultimately, the dry liquids obtained, in contact 

 with them. It was then observed whether they floated or not, and a second set of expe- 

 riments were made with bulbs lighter or heavier as required, until a near approximation 

 was obtained. Many of the tubes burst in the experiments, and in others difficulties 

 occurred from the accidental fouling of the bulb by the contents of the tube. One source 

 of error may be mentioned in addition to those which are obvious, namely, the alteration 

 of the bulk of the bulb by its submission to the pressure required to keep the substance 

 in the fluid state. 



