at the Northampton Meeting, 1847. 



337 



The steam -enpne exhibited by Mr. Cambridge on thii occa- 

 sion materially differed in construction from those he has before 

 shown, for whereas, in the engine which was at Newcastle, the 

 cylinder and valve- box stood inside the boiler, and the crank 

 revolved in the top of the cylinder^, presenting the greatest 

 difficulties in getting at the working parts in case of want of 

 oiling or repairs, the one now exhibited had all these objec- 

 tions removed, as the working parts are placed outside the boiler, 

 a greater length is given to the connecting-rod, and the working 

 parts are kept cool. The steam-pipes of this engine are fixed 

 above the boiler, which has the effect of preventing any accumula- 

 tion of water in the valve- box or cylinder. The fly-wheel is 18 

 inches in diameter larger, and the extra weight of it 2 cwt., caus- 

 ing the engine to maintain a more regular motion. It is altogether 

 more simple, and is made much stronger in all its parts, being 

 capable of w^orking, if necessary, up to 6- horse power. 



The portable steam-engine, applicable to thrashing or other 

 agricultural purposes (4-horse power) ; improved and manufac- 

 tured by Mr. Ogg. — The above has a locomotive tubular boiler, 

 with fire-box surrounded with water, and constructed to consume 

 the smallest quantity of fuel • a dome at firebox-end of boiler 

 for steam chamber, and ash-pan containing condensed water 

 from cylinders, for cinders to drop into; safety-valve fixed on 

 top of dome, and the pressure adjusted by the patent spring 

 balance; whistle, for signal, when required; two steam cylin- 

 ders, supported by brackets upon frame at each side of boiler 

 in a horizontal position, with direct-action, expansive valves, 

 and exhausting into a cistern, through which the cold water 

 from the forcing pump is conveyed in a coil of small pipes 

 before it enters the boiler. Bv this arrano-ement the water 

 becomes heated, and thus prevents that condensation of steam, 

 and consequent waste of fuel, which would result from the injec- 

 tion of cold water. The pump worked by the engine, to supply 

 the boiler with water, is so constructed that it may be disconnected 

 from the engine, and used at any time by hand-power, at a longer 

 stroke, to fill the boiler (when empty) with cold water. The 

 tubes from the fire-box communicate with a smoke-box, placed at 

 end of boiler, upon which the chimney is fixed. At the top of 

 the chimney there is an apparatus which is called a spark-catcher, 

 the importance and advantage of which is, that it is perfectly im- 

 possible for sparks or small cinders to pass through it, even 

 though the draught through the fire and tubes might occa- 

 sionally be powerful enough to bring them into the chimney ; at 

 the same time the draught necessary for the effectual operation of 

 the engine is not in any degree diminished. The steam-engine 

 and boiler are fixed upon a strong oak carriage, with four wheels 



