130 REPORT — 1839. 



table of the machine. Motion is given to this guide by means of a 

 screw, when it describes the exact curve of the slit, and this movement 

 is communicated to the bevelled wheel through the frame to which it is 

 attached. As the part of this guide-rod which, by its traversing, in- 

 fluences the form, is much more distant from the centre of motion than 

 the wheel, any error in the form of the slit will be diminished on the 

 wheel in direct proportion to these differences. The only precautions 

 requisite in using this machine are to ensure that the centre of the cone, 

 which would be formed by the extension of the bevelled wheel, is true 

 with the centre of the bearings ; and that the cutter be so placed, that 

 in the traversing of the machine the centre point shall constantly ap- 

 proach the cutting point of the tool. 



On the application of Anthracite Coal to the Blast Furnace, Steam- 

 engine boiler, and Smith's fire, at the Gwendraeth Ironworks near 

 Caermarthen. By Mr. Player. 



The inconvenience of the fire choking for a long time baffled the 

 experiments made on the subject, but it was at last obviated by heating 

 the coal before it reaches the fire. This was accomplished by supply- 

 ing it, without any mixture of coke or bituminous coal, through a per- 

 pendicular' chamber placed centrally on the top of the boiler, with an 

 opening about 20 inches in diameter immediately over the fire-place. 

 In passing through this chamber, by its contact with the plates, the 

 coal acquires considerable heat, and descending by its own gravity, as 

 the fire consumes beneath, replaces what has been burnt, by which 

 means a regular supply of fuel is furnished, fit for immediate and com- 

 plete ignition. Another inconvenience is also thus avoided, as fresh 

 coal thrown upon the fire abstracts a quantity of heat from the fuel al- 

 ready in ignition, and checks the generation of steam. The fire is 

 never meddled with ; there are no fire drawers ; there is no current of 

 cold air passing through the flues, and a very small amount only of 

 draught is required. One engine worked 72 hours consecutively, du- 

 ring which time the grate neither choked nor clinkered ; nor was a bar 

 used for the fire, or did there remain any considerable result in ashes. 

 The coal was, in this instance, entirely anthracite, (small, but not pow- 

 dery,) and tipped into the feeding chamber once every four hours. 

 Water was also kept in the ash-pit, the steam from which being decom- 

 posed by passing through the fire, the gas forms a jet of flame, creating 

 another active source of power. On these works, there are in action 

 upon this principle, five smith's fires, the tool-maker's fire being blown 

 by a 30-inch bellows only, whilst with this the largest squaring edges 

 for the masons are made with ease. The coal is supplied through an 

 upright brick flue, about three feet six inches high, two feet six inches 

 long, and nine inches wide. The foundry has a similar arrangement, 

 with merely the addition of a flue to take off the flame, the blast being 

 cold, and worked by a small water-wheel, and by which iron is re-melted, 

 running very fluid, and yielding an excellent quality. An oven has 

 also been built for the use of the workmen, heated only with small 

 culm, which succeeds admirably. 



