(1) Cover the metal with sweet oil, well rubbed in, and allow to stand for 48 hours; smear with oil applied freely with a feather or piece of cotton wool after rubbing the steel. Then rub with unslaked lime reduced to as fine a powder as possible. (2) Immerse the article to be cleaned for a few minutes, until all the dirt and rust is taken off, in a generally compressed in steel bottles to a pressure of about 100 atmospheres; but the pressure depends so largely upon the method of filling and upon the temperature, that it cannot be very strictly defined. It is therefore necessary to have a large margin of safety, and before putting a bottle into use it is generally tested to 250 atmospheres. In spite of this precaution, explosions do occasionally occur, and this has created a certain feeling of uneasiness in Germany, where the carbonic acid industry has of late years developed to a very large extent. The use of steel bottles for the transport of liquid carbonic acid was introduced in Germany about four years ago, and now there are over 100,000 bottles in daily use. When the bottles are sent by railway or cart, they are generally only placed in wooden boxes, which is certainly an inadequate protection against rough handling, and shocks in transport.

That an explosion of such a bottle may have serious consequences, is shown by a note which has been read by Guntermann before the German Society of Engineers, describing an explosion of a carbonic acid bottle on board a Rhine steamer. Fortunately the explosion occurred on a Sunday, when nobody was on board; but the amount of damage done to the frame work and deck of the vessel was very considerable, whilst even on shore the concussion was sufficiently strong to break several windows.

The immediate cause of an explosion may be either concussion or exposure to high temperature, and the Fleischer safety crate is designed to avoid the former cause, and to lessen the destructive result if the explosion should be occasioned by the latter cause. The crate consists of a stout iron framework formed by rings and longitudinal bars, which surround the bottle on all sides. A spiral spring is inserted between the bottom of the crate and the bottle, so that if the bottle is carelessly put down during transport, the spring gives and the shock is softened. If, notwith-standing the application of the crate, a bottle should burst, the crate prevents the pieces being thrown about; but there is little probability of the bottle flying to pieces at ill, for if the fracture occurs in the tide wall, it cannot easily extend over a distance greater than that of two consecutive rings of the crate; aad if the battle is blown out the spiral spring will give, and allow the carbonic acid to escape gradually.

The crate has the further advantage that it does not interfere with the filling of the bottle, and is therefore also a protection during the process of tilling; while for transport, the wooden packing cases hitherto customary may be omitted. - (Industries.)

Safety crate for carbonic acid bottles.

Safety crate for carbonic acid bottles.

(4) A very simple but ingenious contrivance - It is so simple that the wonder is the idea has never occurred to anyone before - for protecting the upper portion of carboys when packed in hampers, is called the "Marple Carboy Protector." The main object of this appliance is the protection from breakage of carboys when shipped abroad. It Is well known in the chemical trade that all sorts of devices are made use of to prevent breakage of bottles containing acids and expensive solutions when consigned on long voyages. Some manufacturers even go to the trouble and expense of placing the full carboy (hamper and all), in small empty casks, packing them well with straw, making up the lid, but leaving handle holes at the sides of the cask. Others cover the top of the hamper with a circular piece of timber with a hole in the centre to fit round the neck of the bottle, and then fasten it down to the hamper with pateut package consisting of a stumpy kind of barrel in which the bottle was permanently fixed, embedded in a kind if cement up to the neck, with a lid and handles.

This was very good in its way, but it will be easily understood that expense alone prevented its general " Protector," as will be seen from Figs. 259, 260, 261, is simply a loose lid made lo fit the hampers, and con-lists of two metal rings, the smaller and inner one intended to fit ronnd the neck of the bottle, after being well packed with straw or hay on the top, whilst the larger or outer ring fits just inside the top hoop of lb hamper, to which it will be lashed inth twine or wire. The two rings are braced together with extra-strong narrow hoop-iron, and the whola is then varnished like the "Marple" hampers.

This appliance ensures almost absolute immunity from breakage, and its cost is trifling as compared with other contrivances hitherto in vogue. The only part of the bottle that is exposed is the corked portion of the neck, and as the "Marple " hampers are shaped so as to stow easily in tiers, the slight projection of the cork above the level of the " Protector " is of no material consequence. Wa-may add that as evidencing the practical value of the " Protector," we saw a cargo of vitriol in bottles being stowed in a narrow canal boat - perhaps the most awkward kind of "vessel " to stow carboys in - and with the "Protector" affixed, the carboys were being stowed away in tiers four or five deep like so many drums, and the workmen were standing and walking about on the tops of the bottles as though they were on terra firma.

Bottle packed for protector

Bottle packed for protector.

Rust Removers 500157Rust Removers 500158

The only drawback we can see to the general use of the " Protector " is that when affixed it is not easy to see when the bottle is getting full. This will militate against its use, say for the muriatic acid trade, where the bottles are usually filled by hose quickly, but where bottles are filled by funnel, and a recognised rule adhered to of filling every bottle with a given weight, and no more, of any particular chemical, there is no reason why the " Protector " should not prove as great a boon for the home trade as it undoubtedly will for the foreign trade as regards chemicals consigned in carboys. - (Chem. Trades Jour.)

(c) It has been shown that concentrated sulphuric acid of 66° B. brought into contact with straw, wood, and other organic stuffs at ordinary temperature, can develop volatile organic acids and sulphurous acid in considerable quantity. This sufficiently explains the destruction of iron parts of vessels, etc., not in actual contact with escaping acid, and indicates that sleeping in enclosed spaces in which concentrated sulphuric acid is being conveyed can only be warranted where ventilation is very good.