NATURAL SCIENCES OF PHILADELPHIA. IIT 



respectivel3% The former was, however, entirely peculijir in its 

 Eohaailiidse^ Bathmodontidee, and Anchippodontidse^ and in its 

 almost entire want of artiodaetjles (none with crescent-bearing 

 teeth), while the French eocene possessed non-ruminating artio- 

 dactyles, with crescent-bearing teeth, in its numerous Anoplotherii- 

 dse and Hrjopotamidse. He concluded that there were good reasons 

 for reaardina: the facies as older than that of the Paris basin. 



July 21. 

 The President, Dr. Ruschenberger, in the chair. 

 Nine members present. 



Prof. Persifor Frazer, Jr., made the following remarks : The 

 coal-cutting machine, designed by Mr. Jas. Brown, of Brazil, Ind., 

 and photographs of which were kindly sent me by the inventor, 

 and are herewith offered for the inspection of the members, con- 

 sists of a steel or iron wheel set in a frame, connected with the 

 pneumatic engine, which runs in rails laid parallel to the face of 

 the lieading, which in this case may be several hundred yards 

 long. 



On tlie outer periphery of this wheel are arranged twenty or 

 thirt}^ triangular-shaped pieces of steel, united with it at one of 

 their apices by a pin. In the middle of the opposite side, which is 

 curved, are firmly fixed chilled-steel teetli, which set themselves 

 by friction against the coal to the proper position for cutting, as 

 the wheel is rotated to the right or left. The motion is imparted 

 by Baeans of a small-toothed wheel which moves in rackwork on 

 the under surface of the wheel. 



The machine is suitable for the soft coals of jointed structure 

 (i.e., the black coals), and is operated bj"- causing the machine to 

 revolve against the face of an exposure, and at the same time 

 draw itself forward, b\" means of a rack and pinion attachment, 

 to a middle rail. When it has undercut the coal as far as it can, 

 it is caused to move sideways along the pair of rails first men- 

 tioned until it has cut a channel an inch or two high, four and a 

 half feet deep, and as long as the breadth of the heading. The 

 blocks of coal are thus separated from the rest, except on two 

 sides, viz., the upper and the rear sides, and a skilful miner can 

 knock down with the pick huge cubical blocks, which are com- 

 paratively regular, and suffer less loss by attrition in transporta- 

 tion. 



As in all pneumatic machines the escaped air aids materially in 

 ventilating the mine. 



