L. MECHANICS AND ENGINEERING. 539 



horse-power. Similar attempts, it seems, have previously 

 been made, and careful experiments are needed to show 

 whether they possess any advantage over the best construct- 

 ed vertical wheels ; especially as the comparative difficulty 

 is the escape of the air that has operated on the paddles, and 

 its reflex, by reason of elasticity in the wheel, may produce 

 a sort of gyratory motion or current, sufficient to occasion a 

 loss of power. 8 (7, 1873, ix., 141. 



DESULPHUKIZING COKE. 



Dr. Hoffmann communicates the fact that the sulphur may 

 be completely removed from coke by addition, in quenching 

 it, of acid chloride of manganese, sulphureted hydrogen be- 

 ing formed ; manganese Avitli some chloride remaining as 

 a desirable addition to the coke. The solution of the acid 

 chloride may be made in small leaden reservoirs, and allow- 

 ed to flow into the water-tanks as needed. 6 C,3ay 22, 1873, 

 208." 



CONVENTION OP RAILWAY MASTER MECHANICS' ASSOCIATION. 



The American Railway Master Mechanics' Association re- 

 cently held its sixth annual convention in the city of Balti- 

 more. The attendance was somewhat lander than at the 

 Boston meeting of last year, though it has been pronounced 

 to have been less interesting. Many subjects of importance 

 to the railroad engineer and to the public were discussed, 

 among which may be named the investigation of boilers, the 

 comparative value of fuels, the action of the sand-blast on cop- 

 per, steel, and iron; the economy and efficiency of power- 

 brakes, narrow-gauge railroads, the resistance of trains, etc. 



With regard to the question of the merits of power-brakes, 

 the opinion of the members was uniformly favorable. The 

 Westinghouse, as the best-known apparatus of this class, came 

 in for a good share of attention the committee having the 

 matter in charge expressing the opinion that the saving in 

 expense with the air-brake, with regard to the wear and tear 

 of the wheels and other machinery, is very great, and justifies 

 its use from an economical stand-point. The safety of pas- 

 sengers also demands its use, in addition to which the com- 

 mittee deemed that much of the complaint against the com- 

 plicated nature of the apparatus arises fronj the fact that it 



