GAS, AIR 539 



one of the liquid hydrocarbons. Mr. Thomas Wills, in his" paper read before the 

 Society of Arts, thus describes this patent : 



From the specification which is taken out in the name of Mr. William Wright, of 

 Sheffield, wo gather the following details. A light petroleum, or other spirit, is to be 

 used, as in other cases ; but the apparatus differs from any that has as yet been in- 

 troduced. A number of cylinders of iron or other metal are placed side by side, each 

 being supported in a perpendicular position by means of trunnions, or swivel-joints, 

 which allow of the cylinder being reversed with ease ; in the interior of these cylinders 

 there are fitted a number of fixed pistons formed of cotton or other spongy material. 

 The number of these pistons varies with the size of the apparatus ; a hollow chamber 

 at the top and bottom of each cylinder acts as a reservoir for the spirit, which, in the 

 first instance, is poured in excess through the top, and gradually percolates through 

 the cotton pistons, at the same time saturating them ; the excess of spirit accumulates 

 in the bottom reservoir, air is then driven through the cylinder, and consequently 

 through the saturated cotton. This air enters through the swivel-joint, and passes to 

 the bottom of the cylinder, where it enters just above the bottom chamber, and has 

 to find its way up through the pistons, out at the top just below the upper chamber, 

 and thence down to the opposite swivel-jointmuch, in fact, in the same way as the 

 steam passes into and out of the cylinder of an ordinary oscillating condensing engine. 

 After so much air has passed as to carry away in suspension the greater quantity of 

 the spirit in the cotton, the cylinder is reversed, when the liquid that had accumulated 

 in the lower vessel percolates once more through the pistons from the top to the 

 bottom. In this manner it is found possible to place into the cylinder a known 

 quantity of spirit that shall be sufficient to charge a certain volume of air, and to 

 work it completely out by successive reversals of the apparatus. The swivel-joints 

 are made also to act as stopcocks, cutting off all communication between the inlet 

 or outlet during the period occupied in reversing the cylinder. If a number of such 

 cylinders are used, they are made to communicate with each other, so as to equalise 

 the amount of spirit in each. The air used is supplied from two ordinary gas-holders, 

 but so coupled together by pulleys that one rises as the other descends, a valve opening 

 inwards being placed at the top of each for this purpose. Weights being added to 

 the holder that is full, or, what comes to the same thing, some of the balance-weights 

 being removed so as to allow the full weight of the holder to compress the air, this 

 air is driven through the charging cylinders and can afterwards be used as an ordinary 

 illuminating gas ; at the same time the second holder is rising, and on the exhaustion 

 of one the second is ready by a transference of the weights to supply a continuous 

 stream of air. The work required to keep such apparatus in use does not seem to bo 

 great, an occasional reversing of the cylinders, and the removal or addition of weights 

 to the holder, being all that is necessary. Doubtless even this would be found im- 

 practicable on the large scale, but it is only intended to use this process for isolated 

 buildings and small districts. 



With regard to the character of the gas produced, it is much the same as other air- 

 gases, and subject to just the same laws ; and, of course, this process can claim nothing 

 more than an improvement in the apparatus used for carburetting the air. If air- 

 gases are to come into use at all, and there seems to be no real obstacle to prevent 

 their adoption to a limited extent, the direction for improvement must be looked for 

 in the apparatus employed, and this new patent certainly deserves a fair trial, which 

 no doubt in good time it will have. Probably some means will have to be taken to 

 prevent the reduction of temperature which invariably occurs when evaporation goes 

 on at all rapidly; but as it is generally accepted that almost the shortest possible 

 contact of the air and spirit is sufficient to allow of the former taking up as much of 

 the latter as it is possible for it to do, this cooling may be confined to a very small 

 extent, and may be neutralised altogether, if proper means be applied. It appears to 

 be rather a difficult matter for inventors to obtain the best spirit for the purposes of 

 carburetting air, for we have seen several samples of spirit supposed to be effective 

 for such purposes, which would have been found, if used, of very little if any good, 

 consisting, as they did, almost entirely of a light paraffin oil. The truth is, that very 

 little of the real spirit from the petroleum comes into this country, its exceeding 

 volatility rendering it a very dangerous freight for a ship ; it might, however, possibly 

 pay to have the petroleum sent over in its rough state, and to distil the spirit here. 

 The oil, which is valued as burning material, could be distilled afterwards, and it, and 

 the pitch remaining, would have little difficulty in finding a ready market. If the pro- 

 moters of any one of the recent schemes could command a continuous supply of the light 

 spirit at a reasonable figure, a great advance towards success would be made. That 

 very great interest is still taken in these new schemes by the public is undoubted, and 

 this last one is not likely to form an exception. Meanwhile there is nothing that 

 should be relied upon but a fair trial on such a scale as shall be satisfactory to all. 



