WALKER'S REGISTERED DOUBLE-ACTING SCREW PRESS. Description. FIGURE 1 of the prefixed engraving is a side elevation, fig. 2 a front elevation, and fig. 3 a plan of this press. A A' are the two sills or end blocks, which are cast in one piece with the frames or supports BB, and connected together by the four tierods and nuts CC. Dis the ram, which is made to travel backwards and forwards upon the tie-rods or guides CC by means of two double-threaded screws E E, which are tapped through nuts placed in the two ends of the ram. One end of each of these screws is centred in the sill A', and the other end passed through the sill A. On the A end of each screw there is keyed a toothed wheel F, into which gears a pinion G, which pinion again again is keyed upon a shaft which turns in the socket I, bolted to the sill A, and also carries the fly-wheel H. K is a slotted arm, which is securely attached to the fly-wheel H, and in the slot a of which the handle L is fastened by means of a nut and screw, which allows of its being shifted to and from the centre as required. MM are four rods, which pass from end to end of the press, and serve as a frame for the support of the materials to be pressed. When it is required to use this press, the ram D is drawn to either end of it, and the material-such as leather, Editon goods, hay, of straw-is placed between the ram and the sill farthest from it, and within the rods CC; the handle Lis then shifted along the slot towards the centre of the wheel H, which allows of a quick motion being imparted to the pin.ion G, and through it to the wheels FF and screws EE, which, as they revolve, act upon the ram D, and gradually force it towards the sill, thereby pressing ssing the materials between them. As the materials become compressed, and more power is required, the handle L is shifted along the slot towards the periphery of the wheel H, which thereby gives a greater length of leverage, and consequently increases the power exerted upon the ram. Should this, however, not be sufficient, there are a series of handles placed around the circumference of the wheel H, by which the additional force of two, or even three men may be applied to it. When the ram has arrived at the end of its travel, as shown in figs. 1 and 3, and the material is sufficiently pressed, a fresh supply of goods is placed between the reverse side of the ram and the opposite sill, and the handle being shifted to the centre again, and turned in a contrary direction, the ram is caused to travel back, and the whole process of pressing is again repeated. By the arrangements above described, a very great power is comprehended within a small compass, and the press is rendered double-acting, whereby a very considerable saving in time is effected. WHITE'S PATENT HYDRO-CARBON GAS.-REPORT ON ITS MANUFACTURE, COMPOSITION, AND ILLUMINATING POWER. BY DR. FRANKLAND, F.C.S., PROFESSOR OF CHEMISTRY, OWEN'S COLLEGE, MANCHESTER. (Having given insertion to a paper by Dr. Fyfe, the eminent chemical professor (vol. liii., p. 92), in which the reality of the advantages claimed for this gas was gravely impugned, we deem it but an act of justice also to lay before our readers the principal portions of a Report just made on the subject by Dr. Frankland, of Manchester, who has arrived experimentally at conclusions diametrically opposed to those of Dr. Fyfe.-ED. Μ.Μ.) The experiments detailed in the following pages were conducted at the gas-works attached to the mill of Messrs. Geo. Clarke & Co., Pollard-street, Ancoats, Manchester. These works consist of a bench containing two of Mr. White's resin-gas retorts and two of his water-gas retorts of the largest size, all of which had been in use for four months previously. The water retorts discharge themselves into the resin retorts, and these last work into an hydraulic main, from which the gas passes successively through a refrigerator and wet lime purifier to the gasholder-a vessel of the ordinary construction, and capable of containing about 20,000 cubic feet. The volume of gas produced was measured by a meter placed between the last purifier and the holder. A copper for melting the resin, and an oil cistern for collecting the residual oil, condensed in the hydraulic main and refrigerator during the process, complete the apparatus, the whole of which was placed under my own entire control, and every facility given me for correctly ascertaining the weight and measure of the materials used, and the products of the operations. Before commencing each day's experiments, the cubical contents of the holder were carefully determined, and a specimen of the gas contained in it withdrawn for analysis: the charcoal retorts were then filled, the resin melted in the oil of a former working-about 71⁄2 gallons being used for each 112 lbs. of resin, and the water and oil tanks being first accurately gauged, the process of gas-making was commenced. It was of importance to ascertain the temperature at which the gas passed through the meter, since, if not sufficiently cooled, the indications of this instrument might be far from correct. I found, however, that the gas streaming through the pipes previously to entering the meter had been so perfectly cooled in the refrigerator that its temperature never exceeded 60° Fahr., and was frequently much below this point, thus affording a sufficient guarantee for the correctness of the numbers read off. The illuminating power of the gases was taken by the shadow test, and is expressed in the quantity of gas per hour, which is equivalent to the light of one s. 6. composite candle. The specimens of gas for analysis were drawn from the holder on the following morning, in order to ensure a perfect mixture and a fair sample. I have made the analyses of these specimens with great care, and in all cases over mercury: the olefiant gas was determined by absorption with strongly fuming sulphuric acid-the only method by which an accurate estimation of this gas can be attained: the carbonic acid was determined by a bullet of caustic potash, and the rest of the gases by explosion with excess of oxygen. The prices attached to the several articles employed in the manufacture, are those charged in Manchester, and the value assigned to the residual oil is derived from the price which the hydro-carbon gas patentees give for that article, usually exclusive of carriage. [Here follow the details of five days' experiments.] The foregoing analytical results furnish c2 us with a satisfactory explanation of the processes which go on both in the water and resin gas retorts. In the water retorts two distinct decompositions take place; viz., first, the decomposition of steam by charcoal with the production of equal volumes of hydrogen and carbonic oxide gases; and second, the decomposition of steam by charcoal with the formation of two volumes of hydrogen, and one volume of carbonic acid. This mixture of hydrogen, carbonic oxide and carbonic acid along with a large excess of steam then passes into the resin retort, where, mixing with the decomposing resin vapour, it twice traverses the whole length of the red-hot vessel. There is no doubt that the greater portion of water gas is produced by the decomposition of this excess of steam in the resin retort, since the weight of charcoal required for the formation of the volume of water gas generated in each of the above experiments is more than twice as great as that which disappeared from the water retort. This circumstance elucidates the advantages arising from the passage of this gas mixed with steam through the resin retort, the fuliginous matter which would otherwise accumulate and block up this retort and its exit pipe, as is well known to be the case when resin alone is used, is converted into permanent combustible gas, which, although possessing no illuminating power, yields valuable service in a manner presently to be described. It has been maintained that the hydrogen of the water gas enters into combination with the carbonaceous matters formed in the resin retort, and produces hydro-carbon gases, possessing highly illuminating properties; this opinion originated from the fact that if the mixture of the resin and water gases be not made in the resin retort, but on the contrary, the two gases be conducted separately into the holder, the resulting gas will be greatly inferior both in quantity and quality. The foregoing experiments, however, afford no foundation for this opinion, but, on the contrary, prove that no portion of the hydrogen of the water gas enters into any chemical combination whatever, for, as before mentioned, when steam acts upon charcoal at an elevated temperature, every cubic foot of carbonic oxide produced generates an equal volume of hydrogen, whilst every cubic foot of carbonic acid formed liberates two cubic feet of hydrogen; hence, if the volume of hydrogen contained in the hydro - carbon gas equals the volume of carbonic oxide plus twice the volume of carbonic acid, we have the strongest evidence that no hydrogen has entered into combination, and this is proved to be the case by the results of the first and On the third day a large excess of hydrogen was produced, owing, no doubt, to the decomposition of light carburetted hydrogen by the much higher heat which was employed on that day. But although it be thus proved that the water gas does not in any way enter into chemical union with the constituents of the resin gas, yet I do not conceive that its value in the process is diminished by this consideration. I have already shown its use in taking up and converting into permanent gas much of the fuliginous matter which would otherwise choke up the resin retorts and exit pipes; but even this is of very secondary importance compared with the service it performs in rapidly sweeping out of the red-hot retort the permanent illuminating gases produced by the decomposition of the resin, and in saturating itself with the various volatile hydro-carbons upon which so much of the illuminating power of all gas depends, and which would otherwise, to a great extent, be left behind with the tar and water in the condensers. It is well known how rapidly olefiant gas and all rich hydro-carbons are decomposed into charcoal and gases possessing little or no illuminating power when in contact with the walls of a red-hot retort, and therefore the value of the water gas in thus rapidly removing them from this destructive influence and retaining them in a permanently gaseous form can scarcely be overrated; indeed, this principle has not been entirely neglected by coal gas manufacturers, several companies having attached exhausters to their retorts, which, however, perform their work very imperfectly compared with the water gas. The generation of water gas free from carbonic acid is a problem of great importance, and one which deserves the best attention of the hydro-carbon as manufacturer. The relative quantity of this gas produced varies so considerably (from 10.78 to 4.72 per cent.), owing no doubt to the degree of heat at which the decomposition takes place, and also probably to the rapidity with which the water is admitted into the retorts, that it is not impossible, by varying the conditions, to get rid of it altogether; its quantity appears to decrease as the temperature increases ; but I have hitherto been unable entirely to prevent its formation: it is therefore requisite to have an efficient means for removing it from the gaseous mixture before it arrives at the holder, since this gas is not only entirely useless, being perfectly incombustible, but has a decidedly injurious influence on the combustion of the gas, by cooling the flame, and thus greatly diminishing the illuminating power. Lime, both in its wet and dry state, is quite inefficient for the removal of this carbonic acid, since the carbonate of lime first formed prevents further contact between the gas and the purifying agent. I therefore recommend caustic soda, produced by mixing lime with a solution of common soda, as a most efficient and inexpensive purifying agent when applied in the following manner:-Let 1 cwt. of soda be dissolved in not less than 120 gallons of water (and proportionately for smaller quantities); add to this 70 lbs. or 80 lbs. of quicklime; mix the whole well together, and transfer it to the purifier, where it should be occasionally well agitated: after about 8,000 cubic feet of gas have passed through, the mixture should be run off and allowed to settle in a suitable tank, from which the clear liquor floating above the sediment of carbonate of lime must be pumped up into the supply tank for the purifier, and being again mixed with the same quantity of lime, used as before. Thus little or no loss of soda occurs, this base being simply used as a carrier of the carbonic acid from the gas to the lime. The sediment of carbonate of lime may be thrown away between each operation. The cost of purification by this method would not exceed &d. per 1,000 cubic feet. The following experiment was made with the purifier charged in the manner described, except that only 75 lbs. of soda were employed: cwt. qr. lb. Resin used.......... 207 Coal Charcoal..... Lime, &c Water.. 120 .. 0 0 10 010 026 ...... .. Residual oil produced.. 8 75 gallons. Gas produced........ 3090 cub. ft. per 112lbs. resin 1520 Cost of Production. " 8. d. Resin.......... 2cwt. 0 qr. 7 lbs. at 3s. 6d........... 7 2 " 1st Day. Volume of Gas produced from 1 cwt. Į Resin.. 1300 PER CENTAGE COMPOSITION. Olefiant Gas..... 8.27 Light Carburetted Hydrogen 18.76 Hydrogen 42.03 Carbonic Oxide 30.93 100.00 In order to establish a practical comparison between the partially purified hydrocarbon gas and the Manchester coal gas, as supplied to the town, the latter was conducted from a house adjoining Messrs. Clarke's mills into the dark room set apart for testing their illuminating powers. By a simple arrangement, either of the gases could be passed through a meter which indicated the consumption per hour in observations of one minute. Care was always taken to displace the whole of one gas from the meter before the illuminating power of the other was taken. The following results were obtained: inch. First Experiment. Pressure of Gases, Consumption per hour equivalent to the light of a S. 6 Composite Candle. Manchester Coal Gas. 7 tenths of 1 cubic foot. Hydro-carbon Gas. 74 tenths of 1 cubic foot. Second Experiment. Pressure of Gases, 1 inch. Manchester Coal Gas. Olefiant Gas Light Carburetted Hydrogen Hydrogen ............ .... Carbonic Oxide.. Carbonic Acid 5 50 40.12 45.74 8.23 41 2nd Day. 3rd Day. 6th Day. Average. 1406 1841 1465 1503 7.94 7.78 8.53 8.13 45.06 22.79 32.25 29.71 37.59 50.27 43.62 43.38 9:41 19.16 15.60 18.78 100.00 100.00 100.00 100.00 Consumption per hour equivalent to the light of a S. 6 Composite Candle. Manchester Coal Gas. 8 tenths of 1 cubic foot. Hydro carbon Gas. 7 tenths of 1 cubic foot. This method of determining the relative value of the two gases did not seem to me entirely free from objection, since some of the lighter hydro-carbons contained in the coal gas might possibly become condensed in its passage through the great length of cold piping intervening between the gas-works and the illuminating room; a circumstance which might thus give an undue advantage to the hydro-carbon gas which had to pass through a comparatively much shorter length of pipe. I therefore procured a specimen of the coal gas from the immediate neighbourhood of the works of St. George's-road station, and submitted it to analysis; it yielded me the following numbers, which I have placed side by side with the average composition of the hydro-carbon gas before and after purification: Hydro-carbon Gas before Purification. Hydro-carbon Gas after Purification. .... 7.41 8.13 26.50 29.71 40.27 43.38 18.55 18.78 7:27 .... trace trace trace 100.00 100.00 100.00 As the illuminating power of both coal and resin gases depends almost exclusively upon the quantity of their constituents condensible by fuming sulphuric acid, and which generally appear in all gas analyses under the somewhat inappropriate title of olefiant gas, the superiority of the hydrocarbon over the Manchester coal gas is suffi |