The capital outlay upon the whole installation has been as follows:

:

The cost of repairs averages 2.5 per cent. upon the total capital outlay in works, apart from land, from the year 1891 to 1896 inclusive.

Even more favourable results, as regards maintenance, are being gained with Horsfall furnaces elsewhere, and it may safely be laid down that 5 per cent. on the total capital would be sufficient to cover depreciation as well as repairs on a well-constructed plant, or say 10 per cent. on the cost of furnaces, boilers and flues taken separately.

The cost per ton burned in stokers' wages for the past 12 months is 93d.; the men being paid 30s. per week of six 8-hour days. The nett cost per ton burned, after crediting receipts for mortar and £65 a year saved to the Horse and Provender Committee in coal alone, by using the steam for chaff-cutting, &c., is given as 18. 1d. per ton burned.

The Author's estimate of the saving in coal to the electricity station, apart from any saving there may be in stokers' wages, is 6.3d. per ton of refuse burned, thus reducing the nett cost of burning the refuse to 7·2d. per ton for all charges.

The following approximate statement shows the steam now used at Oldham, it being all at about 130 lbs. pressure per square inch:

Steam from new boiler to electricity station

Lbs. per Hour.

2,985

When the mortar-mills and the machinery in the horse and provender department are stopped at night the amount of steam available for the electricity works is 4,865 lbs. per hour, or, reckoning 20 lbs. steam per I.HP. per hour, say 240 I.HP. Thus it appears that about 70 I.HP. is used for mortar grinding, &c., during the day of 9 hours, in addition to a small amount for

running the day load, and charging the accumulators at the electricity station, while, say, 240 I.HP, can be used for, say, 6 hours at night.

In considering these results, it should be borne in mind that the plant was not originally laid out for steam-raising, and that the Oldham destructor was not only the first upon the Horsfall system supplied to any corporation, but was actually the first high-temperature installation erected anywhere.

The most recent example of the back-to-back type of furnace is the twelve-cell destructor at Hammerton Street, Bradford, Figs. 7, Plate 8, of which six cells started working on the 20th September 1897, the other six being set to work on the 31st January, 1898. In these furnaces two blast flues or air-ducts are built, one at each side of the main flue, and divided therefrom by a 14-inch wall. These flues communicate through suitable openings with the side air-boxes, and valves are provided for starting and stopping the blast to each furnace. This arrangement of furnace is to a great extent on the regenerative principle. Any heat radiated from the main flue is received at the top by the refuse on the drying hearth, and at the side it is received by the air for the blast, which is warmed there and in its passage through the side boxes to 400° F. Thus practically all the heat radiated from the main flue is carried back into the furnaces. The air is delivered into each blast flue by a large steam-jet apparatus, which is built into the down-take flue at the end of the furnaces. There are two down-takes, one for each blast flue. At the top of the down-takes are iron hoods, so arranged as to draw the whole of the air-supply from the deck of the furnaces, thus tending to keep it free from any smell caused by refuse arriving in a stinking condition. The furnaces are fitted with fixed straight grate-bars having fine spaces (1 inch), as are also those at Edinburgh, and much better results have been attained than with the rocking bars hitherto used. With these bars the air is much better distributed and the fire does not burn into holes so quickly as with wider-spaced bars; and another great advantage is that the amount of fine ashes is enormously reduced. The frequent removal of fine ashes from the ash-pits, which is found necessary with large-spaced rockingbars is a most inconvenient operation and greatly increases the labour of working the furnaces. The grates are 5 feet wide by 6 feet long.

The cost of labour in working the twelve cells is, at the date of writing, returned officially as 5 6d. per ton, which is the lowest figure yet recorded of any destructor so far as the Author is aware.

The men work 12 hours a day, and are paid 288. a week for 51⁄2 working days. There are twelve men, six in each shift, three working one block of six cells and three the other; one filling and two stoking each block.

The amount burned is 10 tons per cell per 24 hours, or, say, 120 tons per day total. The blast pressure in the ash-pits is about 11 inch average.

The Author begs to acknowledge his great indebtedness to his Worship the Mayor of Oldham (Mr. Alderman Waddington) for permission to give official figures regarding the cost and working of the plant; and to Mr. W. Jessop, Superintendent of the Ashes Department, for his kind assistance in furnishing the information and in granting facilities for trials from time to time; to Dr. A. B. W. Kennedy, M. Inst. C.E., Consulting Electrical Engineer to the Corporation, and to Mr. T. Wilmot Newington, Borough Electrical Engineer; also to Mr. J. H. Cox, M. Inst. C.E., City Surveyor of Bradford, who supervised the construction of the destructor, and Mr. J. McTaggert, Engineer and Manager, for the facilities and valuable information kindly afforded.

The Paper is accompanied by nine drawings, from which Plate 8 and the Figures in the text have been prepared, and by Appendixes referring to trials of installations embodying the principles described.

OBITUARY.

Sir WILLIAM ANDERSON, K.C.B., F.R.S., D.C.L., was the fourth son of Mr. John Anderson, a member of the firm of Matthews, Anderson and Company, bankers and merchants, of St. Petersburg, and was born in that city on the 5th January, 1834. He received his elementary education in St. Petersburg at the High Commercial School, and even then showed great talent, becoming head of the school, and carrying off not only the silver medal but the freedom of the city. St. Petersburg is a very cosmopolitan place, and he thus enjoyed great facilities for acquiring languages, which, with his natural linguistic talent, he was not slow to make the most of. Thus, on leaving Russia to finish his education in England in the year 1849, he was a proficient in English, Russian, German and French. He had, in fact, two mother tongues, Russian and English, and used either indiscriminately. Even many years after he used to say that he often thought in Russian. He employed his knowledge of that language with great advantage to the Institution by translating and abstracting for the Proceedings articles of interest that appeared in the Russian technical journals, among which may be particularly noticed Chernoff's researches on steel.1

In 1849 he became a student in the Applied Sciences Department at King's College, London, and passed through the course with distinction, becoming an Associate on leaving. He used to tell with pride how he and his friends managed to make the iron castings for some small engines they had in hand. There was no steam-power to work the cupola blast fan, and it had to be done by manual labour, so that the making of a casting was not an easy thing to carry out. On leaving King's College he served a pupilage at the works of Sir William Fairbairn in Manchester, where he remained three years.

His business life began in 1855, when he joined the firm of Courtney, Stephens and Company, of the Blackhall Place Ironworks, Dublin. There he did a great deal of general engineering

1 Minutes of Proceedings Inst. C.E., vol. lv. p. 418; vol. lx. p. 220 vol. lxxxiv. p. 151.

work, including many appliances for railway signalling. He designed several cranes at that time, and Stoney, in his "Theory of Strains in Girders and Similar Structures," refers to the fact that Mr. Anderson was the first to adopt the braced web in bent cranes. To this period of his life belongs his marriage. On the 11th November, 1856, he married Miss Emma Eliza Brown, daughter of the late Rev. I. H. Brown, Incumbent of Knighton, Radnorshire, the ceremony taking place in Knighton Church. In 1863 he became President of the Institution of Civil Engineers of Ireland, to which Society he contributed several Papers.2 During his stay in Dublin he met with a severe accident at Messrs. Manders' Brewery, where he was looking after some work. In some way his right arm was caught between two toothed wheels, which he had already pointed out were dangerous, and the elbow was much damaged. Most of the doctors who were called in said that amputation was inevitable, but his family doctor considered that the arm could be saved. Mr. Anderson decided to act on the latter opinion, the result being that, having a splendid constitution, his arm was restored almost to its normal condition, the only effect being that he was not again able to raise the right hand above the level of his chin. In some things, therefore, he became left-handed, such as in drinking out of a cup or tumbler.

In 1864 Mr. Anderson joined the old established firm of Easton and Amos, of the Grove, Southwark, S.E., and at once went to live at Erith, where the firm had decided their new works should be erected. The design and laying out of these devolved mainly on Mr. Anderson, and although the changes in the class and character of the work carried out since that time have suggested improvements, they undoubtedly were then, and even are now, a model of what such works should be. The particular business at that time was pumping machinery of all kinds, centrifugal pumps, cranes, boilers, and paper and sugar machinery. Mr. Anderson gave much attention to centrifugal pumps, and materially improved the pattern adopted by Mr. Appold. In 1870 the firm took a large contract for three sugar mills for the late Khedive Ismail of Egypt, the greater part of the designing of which fell to Mr. Anderson's share. He spent a considerable time in Egypt during the erection and starting of the mills, and in 1872 presented to the Institution

1 Page 133.

2 Transactions of the Institution of Civil Engineers of Ireland, vol. v. pp. 116, 183; vol. vi. pp. 187, 188; vol. viii. pp. 38, 173; vol. ix. p. 78.

[THE INST. C.E. VOL. CXXXV.]

Y