70 ANNUAL OF SCIENTIFIC DISCOVERY. 



CAST-STEEL AND WPvOUGHT-IIlON BOILERS. 



The relative merits of cast steel and wrought iron for boiler- 

 plates have been practically tested at the Harkorter Works in 

 Westphalia, and the results were decidedly in favor of steel. Two 

 boilers were used in connection with the puddlincr and rolling 

 mills, both of the same form and size, cylindrical, 30 feet lon^, 4 

 feet in diameter, with dome 2 feet high by 2 feet wide ; the thick- 

 ness of the iron plates was a little over four-tenths of an inch, 

 and that of the steel plates one-fourth of an inch, and the respec- 

 tive weights, 8,975 lbs. for the iron, and 5,842 lbs. for the steel. 

 It was found that while a pound of coal evaporated 3.20 lbs. of 

 water in the steel boiler, it evaporated only 2.51 lbs. in the iron 

 one. To perform the same amount of work it required in the 

 wrought-iron boiler 28 per cent, more fuel and 30 per cent, more 

 time. At these works they now liave 15 steel boilers in use, and 

 one of them, which is made of soft Bessemer steel, gives as good 

 results as the others. There was also a marked diminution in the 

 amount of incrustation in the steel boilers, owing, probably, to the 

 extreme smoothness of the surface ; water which gave an incrus- 

 tation of one-eighth of an inch in 2 years in the wrought-iron 

 boilers, gave in the steel boilers an incrustation hardly percepti- 

 ble. — Mechanics'' Magazine. 



The following on the same subject is taken from the '* Scientific 

 American " : — 



" The use of steel in the manufacture of steam boilers is of 

 comparatively recent date, and the relative advantages, if any, 

 over ordinary iron boilers, except on the score of their less weight, 

 has hardly yet been satisfactorily detei'mined. We have before 

 us perhaps the latest information bearing on this subject, being 

 the results of an important series of experiments made recently 

 at the rolling-mills of Messrs. Funk & Elbers, of Hagan, Prussia, 

 for the purpose of ascertaining the respective evaporating power 

 of the new compared with the old style of boiler. 



*' The two boilers experimented with were each 5 feet in diameter, 

 and 34 feet long, constructed to stand 5 atmospheres ' over' pres- 

 sure. One was made of wrought iron, and the other of soft cast 

 steel. The thickness of the sides in the cylindrical portions of 

 the iron boiler was 0.50 of an inch, and of the cast-steel boiler 

 0.33 of an inch. Each boiler had a heating surface of 293 square 

 feet, and 12 square feet of grate surface. Both were new, and had 

 never been before heated. They were setalike in brick-work, one 

 above the other, but entirely separated by masonry ; the gaseous 

 products of combustion passed through a single flue underneath 

 each boiler, and passed directly into the same chimney. At first 

 both boilers were filled, and fires were kept under them for several 

 days in order to dry the brick-work, after which the fires were ex- 

 tinguished and the boilers emptied and cleaned. Each boiler then 

 received exactly 712 cubic feet of water at 95*^ F. temperature; 

 the man-holes were closed, and the water was heated to the boil- 

 ing-point ; again the fires were put out, and all the ashes and coals 



