128 



NA TURE 



[August 6, 1896 



" Klax Scutching and Flax Hacklinc; Machinery," by John 

 Horner, of Belfast. 



" Electric Lighting in Belfast," by Victor A. H. McCowcn, 

 IClcctrical Engineer to the Belfast Coiixiration. 



" Unusual Corrosion of Marine Machinery," by 1 lector 

 MacColl, of Belfast. 



'■ Rope Driving," by Abram Combe, of Belfast. 

 " Description of the Belfast Gas Works," by James Stelfox, 

 Engineer and Manager. 



" Description of the Alumina Factory at Larne Harbour," by 

 James Sutherland, Manager. 



" Partially immersed Sciew-rropeller.s for Canal Boats; and 

 (he influence of Section of Waterway," b)- Henry Barcroft, of 

 Newry. 



The last paper was not read. 



On members assembling on Tuesday, July 28, in the Examina- 

 tion Hall of (Jueen's College, Belfast, addresses of welcome were 

 j;iven by the Lord Mayor of Belfast, Mr. Pirrie, and by Mr. W. 

 H. Wilson, the chairman of the Reception Committee. After 

 this the chair was taken by the President, Mr. E. Windsor 

 Richards, and the first paper was read. 



This was Mr. Horner's contribution on flax scutching and 

 flax hackling machinery. It was illustrated by a number of wall 

 diagrams, without the aid of which it would be impossible to 

 describe the intricate mechanism used in the flax industry. It 

 is a task we will not attempt. A point of economic interest 

 •which came out in the discussion may, however, be referred to. 

 A gentleman connected with the industry pointed out the 

 lamentable waste that occurs owing to the unsatisfactory methods 

 of scutching followed in Ireland. It appears that the flax- 

 growers are always more anxious to get their money quickly for 

 their produce than to get a full return. To scutch flax properly 

 requires time, and also more costly machinery than is generally 

 used in Ireland. On the continent the growers are more far- 

 sighted, and have a larger command of capital ; at any rate they 

 have superior machines, which are more expensive at first cost, 

 and, moreover, take a longer time in performing the operations. 

 The foreign growers have their reward. The yield is 20 to 25 

 per cent, greater than with the Irish machines ; and though it 

 costs about double as much to scutch a given quantity of flax on 

 the continental system, the yield is so much greater that a far 

 larger profit is ultimately obtained. We gathered also from 

 subsequent visits to the flax mills in Belfast that the continental 

 flax is much preferred by the manufacturers, being cleaner and 

 more easily worked. One would be inclined at first sight to 

 attribute these facts to the conservative and shortsighted methods 

 of the people of this country ; for we are very prone to accuse 

 ourselves of errors of this kind. It may be some satisfaction, 

 therefore, to persons of a cynical disposition to find that the 

 generally astute Americans are guilty of a similar fault. Mr. 

 Dobson, of Bolton, a well-known maker of cotton-spinning 

 machinery, told the meeting that there was an immense loss in 

 the preparation of raw cotton, due to the very primitive ginning 

 machinery u.sed by the cotton-growers. It is evident that both 

 here and in America we have .something to learn from the more 

 frugal and painstaking flax-farmers of the continent of Europe. 

 Mr. McCowen's paper on the electric lighting in Belfast 

 followed. The chief feature of interest in the Belfast installa- 

 tion is the fact that all the prime movers are gas engines. Six of 

 these are on the Hartley and Kerr system. They are supplied 

 by Dick Kerr and Co., of Kilmarnock. Four are double acting, 

 with the cylinders working tandem-wise, and having two pistons 

 on the same rod. These engines run at a speed of 160 revolu- 

 tions per minute, and indicate 120 h.p. The number of explo- 

 sions per minute is 320 or 330, or 2 per revolution. The remain- 

 ing two of the six gas engines are single cylinder and double 

 acting. They also run at 160 revolutions, and indicate 60 h.p. 

 The number of explosions per minute is 160, or one per revolution. 

 Naturally the cyclical variation in speed of the tandem engines 

 is very small, owing to the number of explosions, their low 

 initial pressure, and their even distribution ; thenumber of explo- 

 sions being four to one, in comparison with the single cylinder, 

 single acting engine ; there being fcur complete Otto cycles in two 

 revolutions. The method of governing is worthy of attention, as 

 being different from that usually adopted of missing an explosion. 

 The impulses aie continuous, and the supply of gas is graduated 

 per stroke according to the load. The quantity of air supplied 

 to the cylinder is practically constant, the quantity of gas only 

 being varied. This under ordinary cases would lead to a difficulty 

 cJ ignition. As is well known, a poor mixture of gas and air 



ignites slowly ; but it is said that stratification takes place in the 

 cylinder. Taking advantage of this, gas is admitted to the 

 cylinder later and later in the charging stroke ; although even at 

 full power a considerable quantity of air is drawn into the 

 cylinder before gas is taken in. The full supply of air almost 

 immediately follows the piston, while there is only a small 

 portion of rich and explosive mixture near the ignition chest. It 

 will be easily understood that the mechanism by which the some- 

 what novel operations are carried out is of an interesting nature. 

 It was explained by Ihe author by means of wall diagrams; 

 but in the ab.sence of these we can only refer our readers to the 

 iniblished transactions of institutions in which the diagrams will 

 be reproduced. 



These slower running engines drive the dynamos by rope-gear- 

 ing, but there are two smaller engines of the high .speed vertical 

 type, manufactured by the Acme Gas Engine Company of Glas- 

 gow. They have four single-acting cylinders arranged in two 

 lines of two in tandem, working on to opposite cranks. \K full 

 speed they run at 380 revolutions per minute. In the paper 

 tables were given detailing the various conditions of running, 

 quantity of gas used, &c. Without going into the details of 

 these tables, it may be stated that the efficiency of the tandem 

 engines does not appear to be very high, 27 4 cubic feet per 

 electrical h.p. per hour being the best result. This, of course, 

 could be beaten by an engine running on the Otto cycle ; but 

 we must remember that for electric lighting purposes the Otto 

 cycle, with its one impulse in four strokes, is not well adapted 

 unless an enormously heavy fly-wheel be used. It is the old 

 problem that so often faces the engineer : to get efficiency in 

 one direction something has to be sacrificed in another ; and, so 

 far as electric lighting is concerned, the engineer apparently has 

 to choose between an increased consumption of gas, or the pro- 

 spect of unsteady lights. From experience we can say that the 

 Belfast .station gives good results if we simply regard the product. 

 But we believe that when an extension of the station is under- 

 taken — as there is every prospect there will be shortly — steam, 

 and not gas, will supply the motive power. 



On the second day of the meeting, Wednesday, July 29, Mr. 

 Hector MacCoU's paper on the unusual corrosion of marine 

 machinery was read. It appears that a cargo steamer was sunk 

 on the coast of Scotland; she was loaded with "burnt ore," 

 and was under water for a week. On examination, when the 

 vessel was once more floated, the machinery was found to pre- 

 sent an extraordinary appearance. All wrought-iron work was 

 <leeply and roughly corroded, and planed cast-iron work was 

 rendered .so soft as to be easily cut with a knife. As the engines 

 of steamships are generally very little injured by submergence, 

 even for lengthened periods of time, it was evident that 

 there was, as the title of Ihe paper indicated, an unusual cause 

 for this state of affairs. This was found in the cargo. Burnt 

 ore is the residue from the manufacture of vitriol from sulphur 

 pyrites, and is generally found to contain about 4 per cent, of 

 sulphate of copper, together with a little sulphate of iron, due 

 to the sulphur not having been completely burnt out of the ore 

 and becoming oxidised with sulphates. The sulphate of copper 

 would be more or less completely dissolved in sea-water ; and, 

 as the latter contains a considerable quantity of chloride of 

 .sodium, this would react on the sulphate of copper, forming 

 sulphate of sodium and chloride of copper. The sulphate of 

 copper and chloride of copper are both soluble in water, and a 

 solution of either or both dissolves wrought-iron and cast-iron. 

 Thechloride is more energetic in its action than the sulphate : but 

 in time a solution of either, no matter how weak, will dissolve 

 an atom of iron for every atom of copper present. If is satis- 

 factory to know that the author was able, notwithstanding the 

 great apparent damage done, to put the engines and boilers into 

 working order again, and the ship is now doing duty on the 

 high seas. 



The next paper was perhaps the most important read at 

 the meeting ; it was Mr. Abram Combe's contribution on rope 

 driving. As is fairly well known, Belfast is the home of 

 ro])e driving as a means of conveying power from motor to 

 machine ; so far, at any rate, as mill purposes are concerned. 

 The inventor was Mr. James Combe, of the author's firm of 

 Combe, Barbour, and Combe, who are very large manufacturers 

 of flax-spinning machinery. This gentleman in 1856 applied an 

 expanding pulley with V-shaped sides to the differential motion 

 of flax and tow roving frames, convejing the power by means 

 of a round leather rope. He was struck by the efficiency of this 

 gearing, and this led him to try the application of the same 



NO. 



1397, VOL. 54] 



