I 



April 5, 1900] 



NA JURE 



51, 



much higher voltages ; alfo they will be driven from 

 smaller fly wheels by chains instead of belts. The 

 detachment takes with it twenty-five khaki-coloured, 

 long-crank, specially strong bicycles. F'ig. i shows the 

 engine, but I am sorry to say that its dynamo 

 has been removed from its front end and replaced 

 by lugynge. Special spring arrangements at the 

 front end of the engine prevent hurt to the dynamo 

 from jolts. I know of no other compound traction 

 engine whose weight is only 8 tons. I am told 

 that in practice it consumes about 32 pounds of 

 water per hour per electrical horse-power developed- a 

 wonderfully good result for so small an engine (maximum 

 electrical power, probably 13). With a little experience 

 this expendiuire may be nit down to 28 pounds. It will 

 be part of the regular drill of the men to run a search- 

 light for a specified time, there being competition as to 

 the expenditure of coal and water. When we consider 

 that these very economical engines need about 400 

 pounds of water (they need also about 45 or 50 pounds 

 of coal) per hour, we see the defect of the ordinary 

 traction engine for army transport purposes. A third 

 engine which is going out with Major Crompton and a 

 second contingent this week will have partial condensa- 

 tion of its steam, so that the water will not ail be wasted. 

 It is to be hoped that so easily designed a thing as a 

 traction engine with light surface condensing plant con- 

 densing all its steam will be in use before long. Major 

 Crompton has had a considerable experience of engines 

 in general, and of traction engines in particular, having 

 carried out experiments on traction for the Indian 

 Government long before he became identified with 

 electrical engineering. I understand that the War Office 

 is now considering his scheme for working the transport 

 service of an entire division of the army, independently 

 of all railways. 



This is the first time that projectors have been fitted 

 to special trails like gun-carriages. The carriages of 

 riveted best cast steel are strong and light, as may be 

 seen in Figs. 2,3 and 4. The wheels are from the Royal 

 Arsenal, and may be replaced if hurt in the field. The 

 limbers are shown in Fig. 5. Poles and harness equip- 



FlG. 4. — Projectors hauled by men. 



ments for ten span of mules have been provided. The 

 projectors may be hauled either by the engines, or by the 

 mules, or by the men. The projectors are novel in 

 design ; almost the only feature of existing projectors 

 embodied in them is the barrel. Their mirrors, glasses 

 and divergers are mounted in aluminium. They have gun- 

 metal bases moving in ball run turntables. They maybe 



detached from their carriages and stand on the ground on 

 their four feet. The Coles reflectors are of deposited copper 

 faced with silver, and a thin coat of palladium to prevent 

 tarnishing. The lamp mechanism is new, the pattern 

 service lamp being far too heavy and clumsy ; moreover, 

 the usual arc-strikmg arrangement would be hammered 

 to pieces by the vibration of the moving carbon when the 

 lamp is travelling about. The new lamp locks the move- 

 able carbon holder in position after the arc is struck, and 



Fig. 5. — Limbers. 



the feeding movement is carried out by the shunt coil 

 acting on the other carbon. These search-lights may he 

 stationed a mile or more away from each traction engine, 

 as there may be a fall of 52 volts between dynamo and arc. 

 The main cables are of quite a novel kind. They are 

 concentric cables with an insulated core, one-tenth of a 

 square inch in cross section ; they are armoured on the 

 outside by a copper braiding, which forms the return con- 

 ductor, but there are other forms of cable and uninsulated 

 copper ropes for returns. The telephone arrangements 

 are novel. Major Crompton has adopted the Swedish 

 cavalry pattern of instrument, which can be used as a 

 telephone, or the signals may consist of' the "buzz" 

 through a high resistance or through a very leaky circuit. 

 On trial, he finds that there is very good speech through 

 the telephones and two miles of bare wire on the wet 

 grass. Of course there will be audible speech for, 

 possibly, six miles, on dry grass. This fine (No. 22) 

 copper wire may be laid from reels fi.xed on bicycles, 

 when the bicycles are going at ten miles an hour ; 

 and it may be picked up at a speed of four miles an hour. 

 There is also a supply of the more usual concentric tele- 

 phone cable, and twelve sets of combined telephones and 

 buzz telegraph instruments have been sent out. 



I am not at liberty to publish an account of the novel 

 ideas as to the best use of search-lights which Major 

 Crompton hopes to illustrate when in front of the enemy's 

 position. I think that the whole experiment is a hopeful 

 one. Everybody knows the sort of athletic, energetic 

 young men who are chosen for mountain battery work ; 

 they are as resourceful and cat-like as sailor men. 

 Imagine such young men, with, in addition, the qualifi- 

 cations which 1 have enumerated, and you have some idea 

 of these young electrical engineer volunteers. With 

 Captain Lloyd and Major Crompton in command, it is to 

 be expected that there will be a good return for the 

 expense incurred. The money paid for equipment is only 

 a very small part of the total expense of tliis experiment. 



John Pkrry. 



NO, 1588, VOL. 61] 



