In illustration of the rapidity which above all characterises the oxyhydrogen cutting, J. B. van Brussel gives some interesting examples in a paper recently read by him, abstracts of which appear in the Engineering Magazine, as follows: -

An armour plate 160 m.m. (6.3 ins.) thick was cut to a length of 1 metre in ten minutes. A cut of similar length in a plate 15 m.m. thick took less than five minutes, and the cost of application did not exceed 1.50 franc.

To cut a manhole BOO by 400 m.m. (12 by 16 ins.) in a plate 20 to 30 m.m. (0.8 to 1.2 in.) thick requires four to five minutes.

An opening 150 by 150 m.m. (6 by 6 ins.) in a tube 5 m.m.

thick required three to four minutes, while the cutting of the same opening with ordinary tools would need from three to forty minutes, the cost of this work being about fifteen centimes.

Another very striking example was furnished at the station of the Metropolitan Railway at Place d'Italie, in Paris. It was necessary to cut away an iron staircase, 6 metres high, the width of which impeded the traffic. It was cut down to a width of 1 metre in four hours' time.

At Bremen, Germany, the hydrogen-cutting process has been used for breaking up ships, and among other records the following time data are interesting: -

A plate 300 m.m. (12 ins.) thick was cut for a length of 1 metre to a depth of 426 cm. in seven minutes. The same plate had been cut with a. pneumatic chisel along the length of 1.15 metre and to a depth of 1.5 cm., but this work had required one hour.

The hydrogen method was also used for rivet cutting; in less than twelve seconds the head of a 22-m.m. rivet could be burned without any injury to the plate; the rivet was then driven out with a punch.

The maximum thickness which has yet been cut is 210 m.m. (8.27 ins.) in armour plates, but 300 m.m. has been reached in round shafting.

As a matter of curiosity some work done by the aid of the hydrogen jet by the Deutsche Oxyliydric Company may be mentioned. A large bunch of grapes with leaves and branch of the vine was cut out from ordinary thin sheet iron. The imitation was good, and although the piece was of iron, it was very light. A branch of a pear tree with a large nice-looking pear and two leaves, and also a "lily of the valley" were made in the same way.

The following table gives the consumption of oxygen by the Fouche blowpipe, and the time required for cutting up metals of various thicknesses : -

The Chemische Fabrik Griesheim-Elektron gives consumption of gas and cost per metre of cut length as follows : -