cc GENERAL SUMMARY OF SCIENTIFIC AND 



During the last year, also, the employment of steam on 

 our canals became an accomplished fact. From last ac- 

 counts some six boats of the Baxter pattern were plying on 

 the Erie Canal, and a number of others are shortly to be 

 added, capable of making the trip from New York to Buflalo 

 in five days. In this connection, we may mention the novel 

 proposition of Mr. Robert Cheesebrough to keep the canals 

 open in winter by warming the water with the aid of steam 

 ice-melters and breakers. Although the proposition was fa- 

 vorably commented upon in many quarters, it has not yet 

 been practically put in operation. 



Of mechanical interest are the remarkable results attained 

 by Messrs. Iloopes & Townsend, of Philadelphia, during the 

 past year, in punching cold iron. A number of samples ex- 

 hibited at a meeting of a noted scientific body attracted 

 much comment from the fact that one of them had a hole 

 one quarter of an inch in diameter and one inch deep, and 

 others were perforated with a hole half an inch in diameter 

 and one and a half inches deep. The remarkable nature of 

 the results here exhibited (and which it is understood are reg- 

 ularly obtained on the practical scale) will appear when com- 

 pared with the generally received rule of the workshop that 

 " the maximum thickness of iron that can be punched cold 

 is about the diameter of the punch." The depth of the small- 

 er nut referred to is four diameters of the punch, and that 

 of the larger ones three diameters. 



We have no figures at hand whereby to ascertain the pro- 

 duction of coal for the past year ; but from the very general 

 depression of manufacturing industries that has prevailed, it 

 is highly probable that it will fall considerably below that 

 of 1873 and several preceding years. 



In connection with our annual review of this subject, sev- 

 eral items of interest call for mention. 



In the Wyoming coal region, near Wilkesbarre, Pennsyl- 

 vania, extensive and destructive mine fires by some means 

 broke out, and for many months defied every effort to 

 subdue them. Within a short time, however, the persist- 

 ent use of steam is said to have brought the fires under con- 

 trol. 



An apparatus termed the "Aerophore," and which is said 

 to be so much of an improvement upon former attempts in 



