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HOWDEN HOT but it was not until June, 1882, that there was an opportunity of testing it, which was first done in a small two-furnace marine boiler. This boiler was erected in Glasgow, and various trials made, which from the first were so satisfactory that a larger boiler was built for carrying out experiments on a more extended scale, These experiments were carried on at short intervals through the latter half of 1883 and the first half of 1884, and afterwards occasionally as required. These trials, up to February, 1884, and the mode of carrying them out, are partly described in the paper read by Mr. Howden at the Institution of Naval Architects in April, 1984. They enabled him to proportion the air admissions above and below the fuel at various pressures and for various rates of combustion. The relative proportions obtained by these experiments have formed the basis on which all subsequent applications of hot draft in steamships have been made by him. In April, 1884, Mr. Howden contracted with Messrs. Scrutton, Sons & Co., London, to refit the steamer New York City, of their Direct West India Line, with a boiler fitted with hot draft. This steamer had compound engines with cylinders 33" and 61" diameter and 33" stroke, worked with steam of 80 lbs. pressure. The original boilers, which had been in use for five years, were in two parts, placed back to back, so as to form a double-ended boiler with a common combustion chamber. There were two furnaces in each end, having an aggregate grate surface of 75 sq. ft., while the heating surface in the tubes was 2173 sq. ft. The new hot draft boiler was single ended, having three furnaces with a total grate surface of 36 sq. ft. after deduction of side bars, and 37.5 sq. ft. including side bars. This boiler was DRAFT SYSTEM. 71 first tried under steam in September, 1884, and had afterwards a successful trial before loading in the estuary of the Clyde on October 1, and eventually, after loading, another very satisfactory trial on October 13, on which day she sailed direct for Trinidad, which she reached after a successful run without stoppage. As the engines had not been in any way altered during the refit, nor the propeller changed, the difference in results was wholly clue to the boiler. With the original boiler the I. H. P. developed by the engines averaged under 600, with the new hot draft boiler the I. H. P. averaged about 620. The consumption of Cardiff coal with the original natural draft boiler was 13^2 tons per day, while with the hot draft boiler it was on first voyage n tons per day of Scotch coal, but on the second voyage the consumption was reduced to gj4 tons per day of Cardiff coal, and on the third to 9 tons without reducing the I. H. P. This steamer has continued to run satisfactorily to this day. The economy in fuel has been very remarkable, while the power per squre foot of fire grate, from 16.5 to 17 I. H. P., with compound engines, was a new feature in steamship practice. F"ur-ther particulars of the performances of this steamer are given in a paper on "Forced Combustion in Furnaces of Steam Boilers," read by Mr. Howden at the Institution of Naval Architects in 1886. After the New York City had continued running uninterruptedly for a year in the successful manner stated, her performances began to attract the attention of some steamship owners who had obtained particulars of results from Messrs. Scruttons, Sons & Co. These were, however, deterred for some period from refitting their steamers with new boilers on this system, bv the