OlO 



NA TURE 



[April 26, 1894 



which comes on only once in twenty-four hours. Prof. Kennedy 

 found that the total stand-by losses can be reduced in some cases 

 to 8 per cent, of the total fuel ; below this he had not yet suc- 

 ceeded in going, and he thought it was often considerably more 

 than 10 per cent. He was of opinion that the greater waste of 

 fuel occurred beyond the boilers, as it is more easy to get a good 

 evaporation per pound of coal than a small consumption of water 

 per indicated horse-power. Heavy causes of loss are by the 

 condensation ui steam pipes and by leakage. These are pro- 

 bably greater in electric light stations than in most other places, 

 because security requires the use of a very elaborate system of 

 steam pipes. Of steam traps Prof. Kennedy has not much that 

 is iavourable to say ; he refers to them as the "apparatus which 

 we call by courtesy steam traps," and says they require more 

 looking after than the whole of the rest of the machinery put 

 together. He thought also that sufficient attention is not paid 

 to the proper covering of the pipes, including their flanges. He 

 thought the use of super-heated steam might be lound very 

 largely to reduce this particular cause of waste. The cost of 

 oil, water, and stores he puts down as averaging about one- fifth 

 the cost ot coal alone. Discussing the losses between the in- 

 dicated horse-power developed and the records of the consumers' 

 metres, the President said that the loss in the engine itself might 

 be taken as about loper^ient. of the full power ol the engine, and 

 remained very nearly constant at all powers so long as the 

 speed was constant. The efficiency of the dynamo at 

 full load might be as much as 95 per cent., so that 

 the ratio of electrical indicated horse-power of a first-class 

 steam-engine and dynamo might be 85 per cent, at full load, 

 whilst at half load it would be about 76 per cent. This was 

 assuming that the engine drove the dynamo direct, and he con- 

 sidered that direct driving with equal running engines was the 

 proper method of proceeding. The losses between the dynamo 

 terminals and the consumers' lamps in a low tension system are 

 simply losses in the leads ; in a high tension system they cover 

 the losses in general, which are much smaller in the leads and in 

 the transformers as well. Prof. Kennedy did not consider it 

 desirable, however, to enter into a discussion on the respective 

 merits ol the two systems, but stated that as far as the figures to 

 which he had access were concerned, he found that in the case 

 of a low tension system where the maximum proportion of loss 

 in the feeders is allowed to reach 20 per cent, or thereabouts, 

 the actual average loss of energy throughout the whole year 

 amounts to about 10 per cent. This was of course entirely due 

 to ohmic resistance of the feeders themselves and of the net- 

 work. He had no corresponding figures for the alternating 

 current system, but he had reason to believe the total losses both 

 in mains and transformers in the high tension system are not less 

 than 25 per cent, the energy generated, but he thought it certain 

 that this figure will be very considerably reduced in cases where 

 banked transformers are employed with low tension distributing 

 mains. In any case, however, he hardly thought that it could 

 be expected that the total losses would ever be so low as with 

 the low tension system. 



In conclusion Prof. Ivennedy referred to the ease and accuracy 

 with which electrical measurements may be made with con- 

 tinuous currents, a fact which he thought had helped very much 

 in the extremely rapid progress made during the last few years 

 in matters electrical. In the case of the Westminster Electric 

 Supply Corporation, the unaccounted for quantity as between 

 the energy developed at the dynamo terminals and the readings 

 of the metres ot consumers has been reduced to I'.S per cent. 

 Unfortunately alternating current measurements are much more 

 difficult and troublesome, and Prof. Kennedy thought that the 

 fact had, to a certain extent, hindered their adoption. There 

 were, however, he considered alternating current watt-metres 

 practically free from error due to circuit induction and capable 

 ol giving results with quite sufficient accuracy under the actual 

 conditions ol station practice. He believed that very great im- 

 provements in the economy of alternating current working will 

 date in every case from the time when the station commences to 

 make accurate determinations of the true energy generated and 

 the way in which it has been expended. 



At the conclusion ol the address a vote of thanks was proposed 

 by Sir Frederick Ijramwell, as the Senior Pa-t President, and 

 seconded by Dr. William Anderson, the Junior Past President. 

 It was carried by acclamation, and responded to by Prof. 

 Kennedy in a short speech. 



The next business was the reading of a paper by Mr. Edward 

 W. Anderson, of Erith, in which was described the Grafton 



NO. 1278, VOL. 49] 



high speed steam-engine. The design of this novel engine was 

 illustrated by many large cartoons hung upon the wall of the 

 theatre. As we have said, without the aid of illustrations we 

 can only hope to give a general idea of the design of this 

 engine. It consists, firstly, of a foundation casting, the engine 

 being of the vertical type. Upon this casting is erected a second, 

 forming a standard and also a cover for the whole mechanism, 

 the engine being of the enclosed type and the crank shaft running 

 in an oil bath, upon the system common with single-acting 

 engines of this type. The upper casting has a cylinder formed 

 in it by means of two loose liners, one placed in from each end 

 till the liners nearly meet ; the space thus left between them forms 

 the admission port, and, as its width is the circumference of the 

 cylinder bore, its length is only required to be very small in 

 order to get a large area of opening. Communication with the 

 steam pipe is eff^ected through an external annular channel in 

 the casting directly surrounding the space between the two 

 liners or admission port. At a little distance from the 

 steam port the upper liner has a circle of holes drilled 

 through it, which holes open into a similar external 

 annular channel connected with the exhaust branch. The liners 

 are open at both their ends, forming a cylinder, without covers, 

 in which two cast-iron pistons reciprocate. The lower of 

 these is an ordinary trunk piston and has a connecting-rod 

 attaches working upon the centre throw of the crank shaft 

 below. The upper piston serves both for a piston and 

 for a valve. It is essentially a short cylinder having a 

 strong diaphragm across the middle of its length, and 

 just below the diaphragm a circle of holes is cut through 

 the rim of the piston, and these holes communicate, therefore, 

 with the space between the two pistons. The diaphragm 

 in the upper piston has a hemispherical recess ; this receives 

 the steel ball attached to the crosshead. The latter spans the 

 cylinder and acts on the two outer throws of the crank shaft by 

 means of a return connecting rod attached to each end. The 

 advantages claimed for this engine are : — That the waste spaces 

 to be filled by steam are reduced to a minimum, as the steam is- 

 cut off close to the bore of the cylinder, and the long steam 

 passages between the cylinder and the slide valve are done away 

 with ; the weight of the piston and that of the piston-valve, 

 instead of being wholly unbalanced, act in the same line and for 

 the most part in opposite directions so as nearly to balance each 

 other, the result being that the unbalanced moment is small. 

 The valve, instead of having a moving part that is idle as regards 

 the transmission of power, performs the same function as an 

 ordinary piston in rotating the crank shaft. The friction of the 

 valve is also no greater than that of an ordinary piston valve of 

 the same dimensions and stroke. The engine described was 

 single-acting and non-compound, but the author said there was 

 no reason why a combination of engines ranged side by side 

 should not be made to work compound if desired. An experi- 

 ment carried out on a 12-inch engine, working with an initial 

 pressure of 100 lbs. per square inch at 603^ revolutions per 

 minute, indicating a mean of 36 77 horse-power, gave aeon- 

 sumption of 28"2 lbs. of feed water per indicated horse-power 

 per hour. 



A discussion followed the reading of the paper. The 

 general opinion appeared to be that the invention was one of 

 great ingenuity, but no fresh points of importance were brought 

 lor ward. 



Mr. Joy, in his paper, dealt with the hydraulic reversing gear, 

 which he described in his paper read before the recent meeting 

 of the Institution of Naval Architects, and which we referred to 

 in our report of that meeting in our issue of March 22. 



The summer meeting will be held in Manchester during the 

 first week in August. 



WHAT ARE ZOOLOGICAL REGIONS?^ 



'X'HE subject which I now propose to discuss, is thi purport 

 and use, and therefore the essential nature, of what are 

 termed zoological regions. This seems necessary because, al- 

 though such regions have been more or less generally aiopted 

 for more than thirty years, there has of late grjwn up a con- 

 ception as to their nature and purport which seems to ine to be 

 altogether erroneous, and which, if generally adopted, is calcu- 



1 A paper read at the 500th meeting of the Cambridge Natural Science 

 Club, March 12, by Dr. A. R. Wallace, F.R.S. 



