884 KEPORT— 1892. 



Tugs aud salvage steamers can be fitted with the apparatus to protect other 

 vessels in port. 



Sailing vessels not haviii;r donkey boilers require a modified type of the 

 apparatus, embracing a furnace in which to burn coal for the production of fumes. 



Examples are cited of the employment of furnace fumes in extinguishing fires. 



Allusion is made to the frequent practice of using steam against fires in steamers' 

 holds, and the author states his views regarding the capabilities of this system, 

 arguing that, though it is of great value in many cases, it cannot be relied on with 

 certainty. 



9. On a new Form of Steam Brake for Locomotives. 

 By William Cross, O.E. 



It is not known who was the originator of the plan of fitting a small steam 

 cylinder to relieve and as ust the fireman in the hard manual labour of ' setting the 

 brakes/ but so obvious a device was scarcely likely to have escaped attention even 

 in the early days of locomotive engineering. Though the arrangement was ex- 

 ceedingly simple aud powerful it was soon found to possess many grave disadvan- 

 tages, the chief of these being the difficulty of properly graduating the action so as 

 to pull up the train steadily without jerk, and the impossibiUty of keeping an even 

 pressure in the cylinder for any length of time as required vvhen descending long 

 grades. Various forms of reducing valves have been tried from time to tiine, but 

 to the best of the writer's knowledge none of these has proved very satisfactory 

 or reliable in practice. For these reasons it was found the fireman always pre- 

 ferred to use the hand brake, on the action of which he could rely, only using the 

 steam brake in cases of emergency, with the then great probabiUty of either being 

 too late to be of any service, or of its not working properly on account of disuse. 



It seemed to the writer tliat the only way to make a steam brake of real value 

 would be to fit it in such a way that the men were compelled to use it every time 

 they applied the hand brake, and to make its action coincide with that of the latter 

 in such manner that the further the handle was pulled round, the harder the 

 steam brake would go on, and vice versa. 



The practical way Jin which this idea is carried out consists in arranging a 

 floating lever or hunting screw between the usual vertical rod of the hand brake 

 and th'e valve controlling the steam supply of the steam brake cylinder in such a 

 way that, as the man commences to turn the handle to put on the hand-brake, he 

 admits steam to the brake cylinder ; but the piston of the latter, so soon as it com- 

 mences to move, cuts oft' its own supply through the agency of the floating lever. 

 If, therefore, he continues to turn the handle, the piston moves in exact accordance 

 with it until the maximum available steam pressure is reached ; if he now still 

 continues to turn, the hand brake comes into action in the ordinary manner, and 

 this latter also takes place if the steam, were altogether shut oS' from the brake 

 cylinder at the boiler. 



The action thus nearly resembles that used in steam steering gear, gun training 

 gear, steam reversmg gear, &c., aud has been aptly described as ' making a thing 

 move two ways at the same time.' 



10. On a new Form of Gas Engine. By Joseph Day, A.il.Inst.C.E. 



For practical purposes it may be assumed that all gas engines are worked on 

 one of two systems or cycles, viz., that of Beau de Rochas, involving an impulse 

 every other revolution, and that under which an impulse is obtained at every 

 revolution. The former has been made so world-renowned by the Messrs. Crossley 

 that no long explanation is needed. Suffice it to say that in an engine constructed 

 upon this cycle the piston acts alternately as a pump and as a motor. The only 

 objection that can be urged against this system is that as only every other stroke of 

 the engine is available for useful work, the proportions and magnitude of the engine, 

 as compared with an engine doing work at each stroke, must be as 2 : 1. 



