Sir FREDERICK BRAMWELL, Vice-President, remarked that a Paper hrr. Coleman.Mr. COLEMAN said he had not much to add to the written contents of the Paper, except to supply an omission with reference to the indicated HP. of the indicator diagrams. The average indicated HP. of the cylinders of cards, Figs. 13, 16, 19, taken during the voyage to Australia and back was 76 ; the average indicated HP.of the air expansion cylinders was 57 ; and the average indicated HP. of the compressors 118. The total driving power was therefore 133 HP. ; the total resistance was 118 HP., and the difference between the two was 15 HP., and indicated the amount of friction, which was about 12 per cent. I n engines for waterworks and 1;ramwell. Downloaded by [ UNIVERSITY OF SOUTH CAROLINA] on [15/09/16]. Copyright © ICE Publishing, all rights reserve Proceedings.] DISCUSSION ON AIR REFRIGERATING MACHINERY. Downloaded by [ UNIVERSITY OF SOUTH CAROLINA] on [15/09/16]. Copyright © ICE Publishing, all rights reserve Proceedings.] DISCUSSION ON AIR REFRIGERATING NACHINERY.

MAXY members of The Institutionof Civil Engineers may recollect the time when the science of thermodynamics was all but unknown, and when the principle of the conservation of energy, if it was accepted by men of science, was certainly not appreciated by the practical en,' rmeer.In those days a steam-pressure of 5 to 7 lbs. above the atmosphere was considered high pressure; and one of the usual and necessary fittings of a steam-boiler was a vacuum-valve, or safetyvalve, opening inwards, to prevent collapse of the boiler by excess of external pressure. In those days long connecting-rods were considered essential; it was believed by many that a short connecting-rod involved actual loss of power, not merely on account of friction due to lateral strain, but also on account of mere obliquity in the action of the rod. There was also a prejudice in favour of a very moderate speed of piston, which, it was thought, should not exceed a rate of 220 to 250 feet per minute. As the steam-engine, in its infancy, was chiefly employed for pumping, it was natural to make it with a beam, applying the piston a t one end and the pump-bucket at the other. The same form was generally adopted in engines employed for giving rotation to a shaft.Even in marine-engines a modified form of the beam-engine was universal, the beam being in this case divided into two side-levers, which were mounted a t a low level in order to avoid top-hamper, and to communicate motion in a convenient manner to the paddleshaft overhead. For a long period marine-engineers in America adhered to the early form of engine with its beam oscillating high above the vessels' deck. When the screw-propeller began to be adopted, the slowly moving side-lever engine was for some time The discussion upon this Paper a n s taken together with that upon the following one. Downloaded by [ University of Ottawa Library System] on [14/09/16].

No abstract

No abstract

DISCUSSION ON HIGH-SPEED NOTORS. 155Discussion.Sir FREDERICK BRAMWELL, President, in proposing votes of thanks sir Frederick to Mr. Imray and Mr. Kapp, said that the discussion on the two i + a~~l l . Papers had better be divided. First, the subject of motors would be taken, which might be divided into rotary-engines, single-acting reciprocating-engines, and ordinary double-acting engines.The next subject would be that of dynamos, under the three heads of the Hefner-Alteneck principle, the Gramme principle, and the Schuckert principle. Those matters having been treated of, what might be called the general discussion could then be entered on. H e did not suggest that a speaker, when referring to the rotaryengine, should not compare other engines with it, or that he should refrain from touching on the question of dynamos, the object being as far as possible to make the discussion systematic ; but that such system should be so far departed from as to obviate the necessity of any speaker rising a second time.in his Paper. The steam-turbine was one that he made a few years ago, after the fashion of Mr. Froude's liquid brake. There were a number of ratchet-cells in the circumference of the wheel, each of these cells being semicircular in section, and there were corresponding cells in the shell. The steam entered and was supposed to play in a sort of vortex into one cell of the wheel, out of that into the wheel-casing, and so on, following a vortical movement all round until it issued at the outlet. The machine exhibited was what was actually driven. The usual speed was 12,600 revolutions per minute, but 12,000 was about the best. There was attached to it a €riction-brake carrying a weight, so that the power could be calculated.He measured the quantity of steam exactly, and found that it was not economical, using twice as much steam as an ordinary high-pressure-engine. Another specimen of rotary-engine was Mr. Tower's ingenious machine. It was a universal joint enclosed in a spherical shell, with expanding and contracting cavities. I n Mr. Fielding's engine there was also a sort of universal joint, four pistons working in four segments of bent pipe (they could not be called cylinders) upon curved axes. One advantage claimed for it was that the packing was of the ordinary spring-ring kind. He also exhibited one of the engines used in the fish-torpedo by Mr. Brotherhood. It was worked by compressed air. There was also a model of Mr. Brotherhood's com- Mr. GIS~ERT EAPP directed attention to the diagrams illustrative of his Paper, showing that different kinds of field-magnets had been drawn for the same diameter of armature, so as to give an approximate idea of the difference in bulk and weight between the different types of machines. The idea was only approximate, because the same-sized armature in one type might be much more efficient than in another type. Amongst the diagrams there were three different kinds of magnet, which were fairly representative of three types of dynamos used by him under certain conditions. Plate...