Volltext Seite (XML)
THE PHOTOGRAPHIC NEWS EDITED BS T- C- HEPWORTH, F.C.S, Vol. XXXV. No. 1716.—July 24, 1891. CONTENTS. PAGE How Gas Cylinders are Made The “Optimus” Works 522 The Photographic Work of Herschel and Fox Talbot. By William Lang, Jun., F.C.S 523 Affiliation of Societies 525 Some New Addition Compounds of "Thiocarbamide ” which Afford Evidence of its Constitution. By J. Emerson Reynolds 526 Brussels Exhibition 527 Early Bank-Note Forgeries—a Page of History. By John Spiller, F.C.S 529 PAGE Notes 528 Photography in Germany. By Hermann E. Gunther. 529 Recent Developments in Printing Processes. By C. H. Bothamley, F.C.S 530 What Wastes to Save and How to Save Them 531 Photography in France. By Leon Vidal 533 Lighting in Portraiture. By Xanthus Smith 533 Patent Intelligence 535 Correspondence 237 Proceedings of Societies eeee 536 Answers to Correspondents 538 HOW GAS CYLINDERS ARE MADE. The supply of compressed gas in metal cylinders has now assumed the proportions of an important industry, more especially since it was found possible, by the Brin process, to obtain oxygen direct from the atmosphere. The industry is not exactly a new one, for carbon di oxide and nitrous oxide (the latter for the use of den tists) have been supplied in a compressed state for many years. Now, with the creation of the modern amateur photographer who can make lantern slides, and the more general adoption of the optical lantern for purposes of demonstration and amusement, there has arisen a demand for the limelight such as was never experienced before, and as the limelight is dependent upon the two gases hydrogen and oxygen for its support, these gases are now supplied in large quantities commercially. At first the gas cylinders were made of wrought iron; they were cumbrous and heavy, and the pressure of the enclosed gas was so low that a receptacle to hold only ten feet was a most unwieldy concern. But times have changed, and a cylinder of about the same size, but half the weight, is now made to hold four times the quantity of gas at the enormous initial pressure of 1,800 pounds on every square inch. This means the pressure which an ordinary locomotive boiler has to withstand multiplied by twelve. The change is due to improved methods of manufacture, and to the employment of mild steel of special quality in lieu of the wrought iron previously employed. The cylinders are now made without joint or seam, and the process of manufacture is most interesting. A short time ago we had an opportunity of watching the various necessary Fig. 1. operations involved in making these cylinders at the Birmingham works of Messrs. Taunton, Delamard, and Fig. 3. tions it is now heated and drawn out longer and longer, while its thick ness diminishes and its diameter grows less. These operations are carried out by means of a number of hydraulic rams which regularly de crease in size. Fig. 3 roughly repre sents one of these rams with the plunger ready to descend and force its way into the partially formed red-hot gas cylinder, C, and further into the well, W. The plunger may be compared to a finger, and the cylinder to a glove, while the well may represent a hole into which both are thrust in order to reduce the thickness of the glove. With huge tongs the cylinder, fresh from the furnace, is placed in position, but just before the plunger presses into the red-hot cup one of the workmen empties into the latter a little water, so as to partially cool the bottom and prevent it being thrust out by the powerful plunger. Oil is also used plentifully, so Co., by whose courtesy we were enabled to make notes of the process. Beginning with the raw material, we were shown a disc of metal like that shown in fig. 1, and measuring thirty inches in diameter and three-quarters of an inch in thickness. From such a “blank” a cylinder des tined to hold 100 feet of compressed gas can be con structed, and the first operation is to heat the " blank ” in a furnace, and afterwards to stamp it into the cup- like form shown in fig. 2. To all intents and pur- Fig. 2. entire vessel. poses this repre sents the end of a finished cylinder, but it is far too bulky to form the end of one of the size indicated; in deed, it in reality contains enough metal to make the By a series of opera