STANFORD MERTHYR COLLIERY. 



341 



from to 7 cwt. in 141b. divisions. The dashpot is filled with 

 water, till the level of the water is just below the top of the 

 paddle. Under no circumstances should the water be allowed to 

 come above the paddle. One pound of washing soda should be 

 added to the water in order to prevent corrosion of the castiron 

 dashpot. If the pointer is found to be too long in settling, re- 

 move some of the water, and replace it with oil. 



The machine is balanced while empty, and with the slides 

 at zero, by means of the balance ball. All the skips must be 

 brought to a uniform tare so that the poise on the tare-bar can 



Fig. 213. Check Brake. 



be placed at the necessary mark. The poise on the weigh-bar 

 is then placed at some mark a little less than the minimum net 

 weight of coal likely to be in a skip. By this means the weight 

 of the empty skip and the minimum net weight of coal is fixed. 

 Any variations above this is automatically shown on the quad- 

 rant, and is added to the former minimum net weight set on 

 the weigh-bar. The whole machine is cased in wood secured 

 to the floor, so as to protect it from dirt, and also from being 

 tampered with. 



