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THE PHOTOGRAPHIC NEWS. EDITED B T- C- HEPWORTH, F-C.S. Vol. XXXV. No. 1730.—October 30, 1891. CONTENTS. PAGE Gas Cylinders in Transit 745 On the Use of Small Stops. By W. H. Wheeler 746 Printing on Silk 748 The Printing Paper of the Future. By John Howson 748 Compressed Gases 750 Further Notes on Silver Printing. By Lyon el Clark 750 Notes 752 In the Law Courts. By C. Fleetwood Pritchard 753 Paramidophenol 753 PAGE Intensification and Reduction of Negatives. By R. Whiting 754 Photography at the World’s Fair 755 Copying Line Engravings 756 The Chicago Exhibition, 1893 757 Reversed Negatives by Stripping. By A. H. Calderwood 757 Patent Intelligence 757 Correspondence 758 Proceedings of Societies 758 Answers to Correspondents 760 GAS CYLINDERS IN TRANSIT. Now that the lantern season is commencing, and lanternists, both professional and amateur, are busy in looking up and renovating the apparatus which has been lying dormant for so many months, it may be as well if we devote some attention to a matter which, important in itself, has not as yet met with the attention which it deserves. The cum brous gas bags have, in the majority of instances, been discaided in favour of the far more convenient bottles, or cylinders, of compressed gas, and, although a few professional workers still swear by the bags, among whom are those who go in for thunder and lightning “ effects ” with three-decker lanterns, the majority of lanternists who are content with a single, or, at any rate, a bi-unial lantern, carry with them “bottles” and regulators, or “ bottles ” without regulators. The matter to which we refer is the manner of transporting these cylinders from place to place, and the most convenient manner of disposing them while they are furnish ing energy in the form of light to the lantern. We speak of them in the plural because we are in the habit of using the mixed jet fed by two cylinders, but our remarks will apply with equal force to the use of the single cylinder and the blow-through or safety-jet. According to the report of certain ex periments carried out some months ago at Birmingham, a fully charged gas cylinder, although its thickness is but an eighth of an inch, can be knocked about, bent, cast from a height, and otherwise maltreated with impunity, the mild steel of which it is made being of such splendid quality that the cylinder will not only withstand the internal pressure of the gas, which is 1,800 lbs. to the square inch of suiface, but is quite unaffected by the severe treatment already detailed. It is, indeed, a matter of every-day occurrence for these cylinders to be sent long distances by train, and we may say that if an article, whatever it may be, has been so carefully manufactured as to remain intact after having been through the hands of the average railway porter, it must be Samson-like in its tenacity. At the same time, the careful worker will always have in his mind the fact that he is dealing with a machine which contains within itself a vast amount of pent-up energy, and that a nasty knock in the right place might cause its release. The chances are probably a million to one against any accident of the kind. Still, it is the unexpected that always happens, and it behoves him to be careful. But, setting aside all risk of fracture, the naked cylinder is an awkward thing to handle, for there is no handle by which to take hold of it, and it must be carried in the arms like a baby. It is, therefore, advantageous in many respects to have a case for each cylinder in use, and to the best form which this case should take we have devoted some attention. As we have had the cases or boxes which we designed in use for many months, during which they have covered many miles in railway vans and other vehicles, and as these boxes have been found to be most convenient, we will now describe them for the benefit of those who care to adopt the same system. Thecylinder which we employ—we will deal with one only for the sake of simplicity—is of sixty feet capacity, and when crowned with a Beard regulator measures nearly four and a-half feet in length. Its