52 Description of a Self- Ac ting Stopper, 



3, and 4, shew the apparatus in its different positions. The 

 estimated cost of the whole is about 20s. per horse-power. 



John Maxton. 



GtiEENocK, lith Nov. 1841. 



Report of Committee of the Royal Scottish Society of 

 Arts on Mr Maxton''s Stopper for Winding-engines. 



. We have carefully examined and considered the paper and 

 drawings illustrative of Mr John Maxton's invention, for the 

 purpose of preventing the accidents arising in collieries from 

 the over-winding of the ropes by which the coals, &c. are raised 

 from the pit, and we have to report as follows : — 



^ Firsty The apparatus has not, we believe, been yet tried, 

 and in so far as we can form an opinion, without having seen 

 it in actual operation, we consider that there is no practical 

 difficulty to prevent its answering the purpose intended ; and, 

 Secondly^ We are of opinion that much ingenuity has been 

 displayed by Mr Maxton in designing the mechanical arrange- 

 ments by which the object in view is proposed to be effected. 



David Stevenson. 

 Hugh Morton. 

 John Mackie. 

 Edinburgh, IQth May 1842. 



Addendum, 



In heavy winding-engines it is necessary to decrease the 

 quantity of steam as the tub approaches the surface. I, there- 

 fore, think it would be necessary to have a connection betwixt 

 the apparatus and the throttle-valve of the engine, so that 

 the steam could be cut off at the same time that the eccentric 

 rod is thrown out of gear ; and this I think could be very 

 easily effected. 



John Mackie, Mining -Engineer. 



Alloa, 31«< May 1842. 



