270 Chronicles of Science. [April, 



the other proposing to found a bill for their better regulation, on 

 the report of Lord Kinnaird's Commission. Upon reflection, we 

 should hope both these measures will be postponed. 



We have, from time to time, noticed the coal-cutting machines 

 which have been introduced. We have now to record an important 

 movement in connection with them. A committee, consisting of 

 some of the largest coal proprietors of Lancashire and Cheshire, 

 have offered three prizes, of the respective values of 5007., 200Z., 

 and 100?., for the first, second, and third best machines for the 

 cutting of coal. The machines must be adapted to the following 

 requirements : — Thickness of seams, from two to nine feet. The 

 dip, or inclination, from horizontal to an angle of 20°. Maximum 

 size of tub or wagon used in the mines, three feet six inches by 

 three feet, and three feet in height. Grauge of road, from one foot 

 six inches to two feet three inches. It is considered desirable that 

 the machine should be as light and as easily moveable as possible. 



The committee express their belief that compressed air is the 

 proper motive power for working coal-cutting machines. We hope 

 this does not mean, that they exclude machines worked by water 

 pressure from their consideration. The facility with which power 

 is transferred, with scarcely any loss by water, as compared with 

 the great loss when air is employed, renders it advisable that water 

 pressure should be equally considered. Inventors must furnish 

 machines not later than the 1st of November in the present year. 

 We quite expect from this, that we shall soon find coal-cutting 

 machines in general use in our collieries. 



A successful application of the Electric Telegraph has been 

 made by Messrs. T. B. and W. B. Brain, in the Trafalgar colliery in 

 the Forest of Dean. A great difficulty arose in the conveyance of 

 coal from the workings to the shaft, owing to the declivity of the 

 seam under work. Indeed, the steepness was such, that the ordi- 

 nary method of hauling became impracticable. To meet this 

 difficulty the engine at bank was brought into requisition, — to 

 which was applied a length of chain reaching to the end of the 

 workings, the shaft being 200 yards deep, and the dip workings 

 extending to a considerable distance. To ensure safety, instanta- 

 neous communication was necessary, and electricity was thought of. 

 An electric bell is placed in the engine-house, and another near the 

 top of the dip-workings; these are connected by wires carried 

 down the pit and continued along the road. The great danger was 

 the liability of injuring the men, during the rapid ascent or descent 

 of the trucks. To avoid this, " electrical tappers " are placed along 

 the road, and thus at any point a man can signal to stop or 

 start the engine. The old mode of signalling between the 

 " hanger-on " and the engine-man has been superseded by this new 

 arrangement. An instrument is placed in front of the engineer, 



