These figures, multiplied by the actual evaporative powers as calculated, give:
POUNDS OF WATER EVAPORATED FROM 212° F. FOR $1.
Anthracite. Bituminous. Petroleum. Coal Generator Water gas gas. gas.
New York 5040 4643 2948 338 220 577 Chicago 4032 5638 2684 451 220 577 New Orleans 3366 5638 2155 188 220 577 San Francisco 1683 2634 2684 188 179 484 London 4032 6581 1966 751 228 640 Port Natal 1611 1797 1342 Ap- Ap- Sydney 1683 2819 1191 proxi- proxi- Valparaiso 1755 2634 1776 mate. mate.
Anthracite. Bituminous. Petroleum. Coal Generator Water gas gas. gas.
New York $1 00 $1 08 $1 71 $14 92 $22 90 $8 70 Chicago 1 00 71 1 50 8 72 18 30 7 00 New Orleans 1 00 59 1 56 17 90 15 30 5 80 San Francisco 1 00 64 1 50 8 75 9 40 3 50 London 1 00 61 2 05 7 16 17 70 6 30 Port Natal 1 00 90 1 21 Sydney 1 00 34 1 39 Valparaiso 1 00 44 1 03
These figures are very much against the fluid fuels, but there may be circumstances in which the benefits to be derived from their use will exceed the additional cost. It is difficult to make a comparison without considering particular cases, but for intermittent heating petroleum would probably be more economical, though for a steady fire coal holds its own.
At the opening meeting for the winter session of the Iron and Steel Works Managers' Institute, held at Dudley on September 12, Mr. R. Smith-Casson in the chair, Mr. B.F. McCallem, of Glasgow, read a paper on "Steel Castings," which developed an interesting discussion upon steel casting practice. Mr. McCallem said that it was thirty years since the first crucible steel castings were made in Sheffield in the general way, and with one exception the method of manufacture was pretty much the same now as at that early date. The improvement was the employment of gas furnaces instead of the old coke holes for melting. Important economies had resulted from this introduction. Where before it required 3 tons of coke to melt 1 ton of steel, the same thing was now done with 35 cwt. of very poor slack. Though it was apparently easy to make crucible steel castings, it was not in reality easy to make a true steel, that was to say, to make a metal that contained only the correct proportions of carbon and silicon and manganese. The only real way to make crucible castings of true steel was to melt the proper proportions of cast steel scrap with the proper amounts of silicon and manganese to produce that chemical composition which was known to be necessary in best castings. It was in consequence of this difficulty that many makers resorted to the addition of hematite pigs. The Bessemer process was used much more extensively upon the Continent than in this country in the manufacture of castings. It seemed likely that Mr. Allen's agitator for agitating the steel in the ladle so as to remove the gases would be taken up largely for open-hearth castings and open-hearth mild steel, as it had a wonderful effect. The Wilson gas producer, working in conjunction with the open-hearth furnace, had recently produced some extremely wonderful results. In some large works, steel was by its aid being melted from slack which was previously absolutely a waste product. The method of making open-hearth steel castings might be varied greatly. The ordinary method generally practiced in this country was a modification of the Terre Noire process. The moulds employed were only of secondary importance to the making of the steel itself. Unless the mould was good, no matter how good the steel was, the casing was spoiled. The best composition which had been found for moulds was that of a large firm in Sheffield, but unfortunately it was rather expensive. A good steel casting ought to contain about 0.3 per cent. carbon and 0.3 per cent. of silicon and from 0.6 to 1 per cent. of manganese. Such a casting, if free from other impurities, would have a strength of between 30 and 40 tons, and on an 8 inch specimen would give an elongation of 20 per cent. or even more. It was possible by the Terre Noire process to produce by casting as good a piece of steel as could be made by any amount of rolling and hammering.