382 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. 



cooled by the transmission of heat to the water that it only attains 

 red heat. 



A boiler erected on this principle at the Skininygrove Iron Works. 

 Yorkshire, in November last, had the following dimensions : Ten feet 

 diameter and 4 feet from back to front, 110 tubes, of 3 inches 

 internal diameter packed with fragments of fire brick. The gas sup- 

 plied from Otto Hilgenstock coke ovens is mixed with little more 

 than its correct proportion of air. and the mixture is forced into the 

 tubes at about 2 inches water-gauge pressure. The evaporation is 

 5,500 pounds of w-ater per hour, and before being taken over by the 

 Skininygrove Iron Works Co.. it was i-un for a month day and night. 



When one considers that a Avell-known boiler to evaporate 3,140 

 pounds of water per hour occupies about 23 by 13 by 15 feet, it will 

 be seen how great a saving there is in space, 

 t On February 21, 1912, Mr. Ernest Bury, M. Sc, wrote that the— 



Boucourt boiler which \\a.s started up on November 7 last has continued to 

 work very satisfactorily ; its working is almost entirely automatic, and is 

 included in the routine work of the exhaust-engine men, who have 11 running 

 machines under their control. 



The boiler has been off for inspection of the tubes, which proved to be clean 

 and free from scale, a fact which I attribute to highly rapid ebullition. During 

 the length of time the boiler has been at work we have had no trouble with 

 priming, at all times the steam having been perfectly dry. 



The average temperature of the waste gases leaving the plant has been 

 78-80" C, which is ample proof of the boiler's efficiency. 



Generally, I consider that the boiler has come up to exijectations. It is cer- 

 tainly the cheapest method of raising steam which has yet been devised. 



SIR AVILLIAM RAMSAY'S PROPOSAL. 



The proposal to burn the coal in situ and bring the gases to the 

 surface, when the ammonia, etc., can be extracted and the gases 

 utilized for power, has attracted a good deal of attention. 



That the coal when fired will keep alight for years and give off 

 useful gases is quite Avell known. In New South Wales there is a 

 seam of coal Avhich has been alight for many years, but it is near the 

 surface, and the air can get down fairly easily. With the deep seams 

 of this country special provision would have to be made. 



For burning out seams in old collieries the scheme is vei-y at- 

 tractive, because shafts already exist, and there are many seams 

 which are too thin to work in the ordinary way. The limit for 

 economical working appears to be 12 to 15 inches. Lidgett Colliery, 

 near Barnsley, worked an 18-inch thick seam for many years, but it 

 closed this year. There are, however, several other collieries in 

 Yorkshire working seams in the neighborhood of 15 inches thick: 

 one colliery near Wakefield having a seam 16 inches thick. In these 

 very thin seams the men have to go along the gate roads laid on low 

 trucks, face downward, and they propel themselves forward with 

 their toes. It really is surprising that men can be found to under- 



