Society of Motor Omnibus Engineers.
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Paper by Mr. Worby Beaumont.
The title given to me for this paper, namely, " The evolution of the Motor Omnibus, and a forecast of the ultimate Lines of its development," was, I think, invented by your Secretary, who did not quite like to say that the title should be " Motor Omnibuses in ' Esse ' and in posse." It is one which, I believe, I accepted, and accepted too readily. Too readily, because it cannot be treated in anything like the fullness which so ambitious a title requires, and because, 3 fear, it may have raised expectations that cannot be realised in a short paper. I am addressing an audience which is fully acquainted with everything I may touch upon in deal
ing with the subject of the whole title, or any part of it, and I must, at the outset, therefore, crave indulgence of the members of this Society in respect of the brevity and incompleteness of this paper.
A Historical Survey.
The evolution of the motor omnibus may, for all practical purposes, be said to have begun in England with the work of Hill, Squire, Gurney, Hancock, James, and Dance, between the years 1824 and 1835, although steam-propelled vehicles had been made before this period.' The steam coaches of Gurney, James, and others were all made with large driving wheels fixed on the crankshaft of the steam engine, as, subsequently, adopted in the railway locomotives. The speed of the engine was, thus, only that of the driving wheels, and, hence, necessarily, a slow speed, which meant a large and heavy engine. The weight, however, was not as great as might have been, even in after years, expected, partly because of the high mechanical efficiency of the direct drive from long-stroke piston to crankshaft, and partly because they used pressures much higher than those used by any steam engines then or for many years later. Most of the coaches were -built on horse-coach lines, and those of Gurney, carrying 14 passengers, weighed about 65 cwt. The engines used by Gurney, in the coaches he ran to Birmingham and elsewhere, had two, horizontal cylinders, 9 inches in diameter and 18 inches stroke, and the driving wheels were 5 feet in diameter. Gurney's boiler was the forerunner of the many forms of water-tube boiler since made, and the details were very cleverly worked out by him, and, also, by Sir Charles Dance. The fuel was carried on the lower layer of tubes, and the air was supplied to the fire by means of a fan driven by a horizontal donkey-engine, which was, also, the feed-pump engine. A large proportion of the exhaust steam was condensed in the feed-water tank, the out-flow from the upper part of which was directed to the chimney, where it was slightly superheated before its escape. The pressure used, generally, varied from 7o1b. to about szolb., which was often exceeded, the boiler being tested (cold) to 800lb. per square inch. About so gallons of water were used per mile, and about zolb. of coke, from which it Vould appear that the steam consumption was from olb. to 65th. per horse-power per hour. Considering the various imperfections, and the incomplete protection of the engine and steam pipes from condensation, this was not high, but it was higher than that of the more-completely protected engine, and better arrangement of engine and boiler, in the Hancock coaches. Gurney made several forms of his vehicle, one of which was a most successful tractor, or road locomotive. He, for some time, used one of these tractors on a colliery railway in Wales, with remarkable results as to the possibilities of the design for this purpose.
An Early Differential.
A very distinct departure, in the general construction of his coach, was n-made by Hill, who used a long frame fitted with horn-plates for the driving axle, and with long, and nearly flat, leaf springs over the axle, the frame being suspended in what, afterwards, became locomotive fashion. The springs for the front axle were, also, above the frame, which was suspended from them. Hill, however, was of later date, viz., 184o and, some time later (1843), he designed a coach in which, for the first time, a " Jack-in-theBox," or differential, gear was employed. Hancock, whose work in the evolution of the steam coach was, perhaps, more important than that of any of the others, used several different forms of vehicle, and employed a vertical engine, and a very ingeniously-constructed boiler, consisting of flat, thin chambers like a large number of flat paper bags, placed side by side, and clamped together between strong cast-iron plates. On the driving axle was a sprocket wheel, on which ran an ordinary chain driven by a sprocket wheel of the same size, on the shaft of the engine. This was the first instance of the use of a separated engine driving by means of a chain. Although, however, this form of drive was employed, Hancock did not use the opportunity that one thinks it might have given him to use a smaller, higher-speed engine. This, nevertheless, is not surprising, when the difficulties which met the constructor of steam engines and boilers, in Hancock's time, circa 1830, are remembered. Hancock was the inventor of that form of wheel construction which is, now, because it was many years afterwards adopted for the wheels of gun carriages, commonly known as the artillery wheel. He called them his" wedge" wheels, because the root of every spoke was of wedge shape and, like the voussoirs of an arch, fitted together and made a solid wheel-centre. This is another feature of the evolution, which has remained without change, in principle, to this day.
Pre-Victorian Steam Omnibuses.
It may be as well to record, here, that the coaches made by Hancock were no mere paper vehicles, for they ran very con siderable distances, in actual public servioe. One of them, for instance, which was fitted with a char-A-banes body to carry 22 passengers, was put to work, with others, on a regular service between Stratford, Islington, and Paddington, and the service made 4,200 miles, and traversed the City over 200 times. Another point, in the evolution of the motorbus, was the invention of what was known as the Ackermann axle. This was patented, in 1819, by Ackermann, as the importer of the invention of one, Lankensperger, of Munich, who designed it with the object of increasing the size of the front, or steering, wheels of ordinary horse vehicles. It is of interest, however, in this connection, to note that a modification of Ackermann's design, for use with all four' of the wheels of a vehicle, was made by Gibbs and Chaplin, in 1832, for a vehicle designed to act as a trailer, with all the wheels radiating, so that they automatically followed any curve described by the pulling vehicle. This device has not, yet, been used on motor omnibuses, but an approach to it is seen in certain vehicles which have been made on the Continent.
The success of Hancock, Gurney, and others would, undoubtedly, have led to the rapid development of steam coaches on common roads, but for two causes. Firstly, the destructive opposition of the many interests associated with the, then, universal horse vehicles ; and, secondly, the advent of the railways, which, quickly, took from the roads the greater part of the whole of the coach traffic, and a very large part of the whole of the other traffic, the existence of which made the high roads of greater importance than they were, subsequently, for many years.
It cannot be doubted, that the work of the men named had some influence in subsequent design, although the long period between 1835 and 1896 was sufficient to obliterate, almost, the memory of what they had achieved.
The desire to travel by mechanical means on high roads broke out again, strongly, about a quarter of a century after all this work had been consigned to the scrap heap, but the first efforts in the revival, in spite of the advantages of manufacturers with regard to materials and appliances, were of more importance to the traction-engine designer who, subsequently, appeared', than to those who wOuld make a steam carriage. This may be said of the road steamers, made in 1858 and 186o, by Ricketts, at Buckingham, for the Marquis of Stafford, and another for the Earl of Caithness. In 1862,
however, Messrs. A. F. Yarrow and Hi!ditch showed, in the Exhibition of that year, a vehicle which was a considerable improvement on its predecessors. Although the construction of such vehicles was given up by Mr. Yarrow, who is so well known to us all in connection with the torpedo-boat, because such vehicles could not be used under the laws of Great Britain, several other links in the evolution of a satisfactory road vehicle were devised and used when the police were not looking, by, among other, Messrs. Tangye (1862), Mr. A. Pattleen (1862), Mr. Percy Holt (1867), and Mr. H. A. 0: Mackenzie (1870 There was, however, one common fault, with all these, as well as with the Thompson road steamers, which were fitted with solid-rubber tires, viz., that the boiler, or steam generator, formed so large a part of the whole weight, and introduced so many inconveniences. The carriage made by Pattison had a large, vertical boiler, with a pair of small, steam cylinders geared to the driving axle. Holt's road steamer, which was fitted with a good type of fire engine boiler of the period, had two, double-cylinder engines, coupled to short crankshafts on the outer ends of which were sprocket wheels carrying a pitch chain. These engines were designed for a very high speed of rotation, as compared with any of the engines previously made for the purpose, the speed of the engine being about six to one of the driving wheels. Although a pressure of about 2so lb. was used, the boiler formed too large a part of the carrying'% capacity of the vehicle, and, with 'respect to all these middleperiod vehicles, it is curious that the designers seemed not to know of what had been done, round about 1830, in the design and construction of very small, high-capacity, highpressure, steam generators.
Modern Steam Omnibuses.
Leaving, now, this earlier period of the evolution, a consideration of which your Secretary has imposed upon me, we come to the evolution of the motor omnibus as we know it to-day. These may be, broadly, classed as of two kinds : the steam vehicle, and the petrol-motor vehicle. Reference to the former follows, naturally, on the reference which has been made to the steam coaches, or omnibuses, of past days. The invention, by the late Leon Serpollet (whose early death all, especially those who knew him, most deeply deplore)of his type of instantaneous generator, various forms of which, by the by, were invented at the time of the activity of Hancock, Hill, and others, gave an impetus to the design of steam vehicles, and steam tramcars, using boilers of high generating capacity for their bulk, very high pressures, superheated steam, and very small and high-speed engines. For a considerable time, after sufficient success with small steam carriages, round about 1896, Serpollet devoted most of his attention to the adaptation of his system to tramcars, a good many of which have, for some time, been in use on the Paris lines. He returned to the construction of the smaller vehicles, about five years ago, and a good many of the Serpollet carriages, of various sizes, were made, and are still being made. More recently, he turned his attention to the adaptation of the system to the motor omnibus, and, in connection with another firm, it is known as the Darracq-Serpollet. Possibly, more may, in the future, be heard of these vehicles, with regard to London use.
The 'steam omnibus is represented, at the present time, by those of the Clarkson Company, and of them there are about 50 employed by the London Road Car Company, the London, General Omnibus Company, Messrs. Burtwell Brothers, and Messrs: Sharland. Of the construction of this omnibus, it appears to be, now, unnecessary to enter into details, because a very complete description of them was, recently, given, by Mr. T. Clarkson, in a paper read before the Institution, of Mechanical Engineers. It is sufficient to say, here, that the first of the Clarkson vehicles used in London were of the single-deck type, and their running, for some months, was so encouraging that the London Road Car Company ordered a numberof the large, double-deck vehicles on the same system.. A number of the single-deck type have been running; with dividend-paying success, for son-le years, at Torquay, but the Torquay Company, having received a good • offer for their vehicles, for use in Harrogate, have, in conseauence of the near completion of electrical tramways in Torquay, accepted that offer.
The steam-propelled vehicle has some advantages, at present, over any.other form of motor vehicle, if cost of propulsion is included in the consideration, cost being the one . objection, now, acting detrimentally against the one thing thatis superior to the steam vehicle, even when its chief advantages are under review, viz., the electrical motor. With the steam engine, gradual but rapid acceleration is possible; the engine may, always, run quietly, and much less gearing is required between engine crankshaft and road wheels. In sonic cases, economy may be urged as a further advantage, but, where kerosene is used for fuel, the claim for economy does not appear to be supported, in practice, so long as the price of petrol is not more than about double the price per gallon of kerosene.
Predominance of the Internal-Combustion Engine.
Of the total number of omnibuses running in London, only about 5 per cent. are, at present, steam omnibuses, and the various omnibus companies are adding, rapidly, to the numbers they already possess of the petrol-motor omnibuses. • The reason for this has, probably, some explanation beside that of difficulty of obtaining steam vehicles more rapidly. It has been urged that, if the steam vehicle had only the steam engine, it would be perfect, but that, having a steam generator and steam pipes, and steam fittings, feed pumps, feed-water pipes and regulators, all under, at all times, the highest pressure at any time available on the engine pistons, it is not, yet, as perfect as it would be if these various parts could, under the conditions of the working of an omnibus, be maintained in absolutely tight, working condition. In the evolution of the petrol omnibus, we arc, first, driven to our acknowledgement of the petrol-motor lorries, made by the Canstatt Daimler Company, and sent to this country, for the Automobile Club Trials at Richmond, in 1899. These vehicles contained, in their main features of design and arrangement, the features of many of those that have followed, and, in recognition of this, gold medals were awarded to these vehicles in expectation that their then promise would lead to important developments. This expectation has been realised, and even the latest forms of the vehicle, now known as the Milnes-Daimler, great as is the development since 1899, are, in spirit of arrangement, that of the early vehicle. It would be a waste of the time of this meeting, if I used any of it in describing the differences in construction of the various, petrol-motor omnibuses now at work in London. Most of the members of this Society are fully acquainted at least with all the main points that would be included in such a description.2 I will, therefore, • only refer to some questions relating Lo design, in practice, and use, of the vehicles generally.
The Vehicle and its Road.
A railway consists, mainly, of three essentials : (r) a smooth, steel road, carefully made and maintained; (2) a. locomotive ; and (3) a carriage; or a train of them. The road is an inseparable part of this combination, and renders it possible for the whole machine : (a) to carry a large number of people ; and (b) to carry them quickly. The motoromnibus owners are trying to get, and to offer, the advantages of the combination of the three elements forming the railway machine, without the advantage of the possession of one of those elements, viz., the smooth, level, steel road. In this fact lies the first great limitation of the practical,
commercial use of the motor omnibus. In this lies the limitation of speed, and, so long as this limitation is ignored, so long will the Herculean task of maintaining motor omnibuses in order be the more difficult, and the possibilities of continuous profit on their running the more remote.
The motor-omnibus constructor has combined a delicate motor and a carriage, and has produced a locomotive carriage which has to work, always, under conditions as to road which may be likened to the railway machine trying to run with one of its three elements always out of order. That they have succeeded in offering comfort, with celerity, under the conditions, is sufficiently remarkable; but, if a comparison of the conditions and circumstances is pursued, it becomes even more remarkable. With all its road advantages, the railway train of to-day weighs at least 20 cwt. per passenger, and the electric tramcar on rails about cwt., whilst the motor omnibus weighs under 21 cwt. per passenger, and has no such road. The heavy deadweight of the railway train may be excused on several grounds, including space per passenger and speed, but it is questionable if the weight of rolling stock of many railways will not . have to be materially reduced in future. High speed is one of the first considerations on the railway, and the provision of power for this provides the power for acceleration : the motor omnibus must run at a comparatively low speed; its total weight must be small, and, yet, it must have the power required for a sufficiently rapid acceleration. The weight of the engine, or motor, of the railway train, on smooth, level rails, may approach 2 cwt. per horse-power : the engine of the motorbus must not weigh a tenth of this. 'She railway train runs on a road that is entirely under the control, and maintenance, of the train owners, and, hence, may be kept in the condition suitable for the working of its machinery : the motor omnibus must run on any road that is not bad enough to justify its entire remaking, Thus, the motor omnibus, which requires within itself the highest order and class of prime mover and transmission machinery, must, at present, work under most disadvantageous conditions and circumstances with regard to that which is the equivalent of one of the three great elements of the combination which makes up the railway machine.
Present-Day Requirements.
The motorbus problem, both now and in the future, is a road problem, as I have urged, to the best of my ability, for some years, and, especially, since 1898.3 In as much, however, as we cannot wait for such road improvements as are inevitable, even if only to the advantage of horse traffic, it is obvious that the development of the motor omnibus has to be oonsidered with reference to the conditions imposed with the roads as they are at present; and as they will be in the very near future. This being so, it may be asked, what is wrong, then, with the better types of motor omnibuses of to-day? To this question, I would reply, that the first and most pressing improvements are those which relate to the methods and practices of usage of the omnibuses. Firstly, more attention must be given to the requirements of the motor omnibus as an intricate machine. Secondly, and to this end, more attention must be given to the requirements of the motor-omnibus engineers, who have the responsibility of maintaining the omnibuses in a fit condition to be kept on the road. Thirdly, the maintenance of the moior omnibus, being placed under the superintendence and guidance of trustworthy and competent motorbus engineers, those engineers must be allowed to be the best judges of the requirements of their department. Fourthly, the judgment of the motorbus engineer, who is responsible for the maintenance of the motorbus in running order, must be final as to that condition, and not that of the traffic manager. Fifthly, the running of a number of motorbuses means the maintenance of a lot of machinery. This last-named requirement, according to the number of motor omnibuses, means an engineering works with good equipment of tools of various kinds, and more or less in number, and workshops of proper construction, and of character suitable to the kind of work which has -to be done in them; there should be workshops and appliances, which must not be inferior to those of engineering works wherein are made gas engines, petrol engines, and the highest class of millwright machinery. The shops and appliances must be such as will enable men occupied upon the delicate and highly-accurate workmanship to do their work conscientiously and, at least, not in discomfort. In these shops, there must, always, be properlyand systematically-kept stores, and, in the larger shops necessary, where a large number of omnibuses are maintained, there should be, under the engineer, a foreman who fully understand-s the construction and fitting of petrol engines, or of similar, high-class, minutely-accurate fitting, and a foreman for all the transmission-gearing work and operations. This may seem to be a call for a very large expenditure, but, considered with reference to a number of omnibuses, and with the imperative necessity for thoroughly-good and comprehensive maintenance work, that expenditure is not only necessary, but is the means of makin‘, because of saving, money. To inaugurate the ownership of motorbuses, for public service under conditions which T have had to condemn in several cases, namely, by buying a few omnibuses, and by commencing to run them with either no provision for maintenance, and no workshops, or only a shed or two and a few tools that might be useful to a country blacksmith, with no stores, no stocks
of material and components, unless petrol, oil and grease be considered part of stock, is to court failure, and, generally, the courting has been successful.
The Penalty of High Speed.
The next point to which I would refer, with regard to lines of development, is the reminder that it is well to learn to walk before trying to run. The present motor omnibus, of the batter kinds, is a satisfactory vehicle, if those who use them could be persuaded that it is better suited for a moderate speed than for racing. The motor omnibus which, with its load, weighs 6,i, tons, running, as it often does, at 14 to 18 miles per hour, especially when running home at one o'clock at night on some of the lines, reminds one of an ch phant bought by an ill-advised purchaser for the purpose of running in competition with an Arab steed, and one of the first necessities in development is not change in construction, except in so far as gear ratios are concerned, but in the use of the present vehicle with regard to the speed at which it is forced to run. The mere fact that the elephantine omnibus can be run at these speeds is no more reason for running them at these speeds than there would be for loading a girder so that the stress in the materials was, say, 30 tons to the square inch because it was known that the ultimate tensile strength of the material was 31 tons ! It would be good policy, so to arrange the engine and gear of a motor omnibus, that the driver could not, under any circumstances for London use, exceed, approximately, 12 miles per hour, the gearing being, also, so arranged that he could, under the conditions of traffic running, maintain a high average speed, so that little time would be lost on such hills as are, mostly, met with in London, the power already common on these vehicles being sufficient for the purpose without going to the high powers which have been fitted to some. The engines would, of course, have to be fitted with governors that are governors, and with wearing surfaces of fork, collar, and pins designed with a view to durability. It may be said, that a maximum speed of about 12 miles per hour is insufficient ; but this would not be the case, and the statement could, only, be supported, at the present time, because so many of the omnibuses are running at high speeds, which are unnecessary, uneconomical, and suicidal. I have, very often, urged the objection to high speeds; but I feel it necessary to do so again, because, not only are they bad for the reasons given, but they are the cause of a large part of the whole of the noise made, even by the best of the omnibuses running, when they are on roads of average condition, and still more so on the many very holey, bumpy roads in and round London. A maximum speed of 12 miles per hour would, moreover, at least equal the speed of a hansom cab, and, with the power and arrangement of gear ratios, and with the mechanical efficiency of the best buses, the average speeds would, always, be such as to make them 50 per cent. faster than the horse omnibus. It is true, that the very high speeds please some people, even on bad roads; but that which is commercially possible must be considered by the owners of things purchased for commercial purposes, and it will he much better so to work motor omnibuses, now, as to enable them to be kept on the streets, than to run the risk of commercial failure, and of opposition by the many to whom they are, as at present run, a positive and real nuisance. For example, in certain streets and roads where the surfacs. is bad, objectionable vibration is set up by the high-speed running of a vehicle weighing from 4 to 6 tons with its load, even although that s-ehicle runs on rubber tires. These same tires, however, are sometimes, thin, and hard enough to afford comparatively little cushion between wheel and road.
The Evils of Forced Working.
Another important question, in this connection, is the distance run per day. with the present omnibuses, on the roads as at present maintained. The high speed, of which I have complained, is not only the cause of the troubles already referred to, but it enables the omnibuses to be run 120 miles and more per day in the 16 or 17 hours which is its day's work. There are, thus, only left the few hours, Iron 12 or x o'clock at night to the very early hour in the morning at which the bus must leave the yard. In these few and unsatisfactory hours of the 24, a four-cylinder, gas engine. with its gas producer or equivalent, its water cooler and air draught, water pump, water-circulating system, its magneto and electric-ignition apparatus, its lubricating system, and all its fixings, a driving clutch and its connections, a transmission shaft and its bearings, a change-speed
gear box with all its gear-box bearings, lubricators, fixings, change-speed lever connections, propeller shaft, and universal joints, and the final driving gear, either by live axle and Its differential gear, and other parts, or by transverse shafts and spur gearing, or by transverse shafts, differential gear, and chains, all the gear and parts of two or three sets of brakes, four wheels and sets of axle-ends, and steering gear, all the underframe and spring suspension gear, all the many hundreds ot parts, bolts, nuts, rods, pins, lubricators, and pipes, all these have to be, or should be, carefully looked over, by competent men, with assistants with spanners and other tools in hand, so that, not only is that which is obvious attended to, but so that the detect or looseness which is not obvious may be discovered. The more completely this is done, the fewer will, ultimately, be the necessary renewals, and the less the labour in maintaining a thorough inspection. If the omnibuses ran only 90 to too miles per day, la; even less on some of the very bad roads, no more time in the garage would be obtainable, but the present heavy cost of repairs and renewals might be lessened materially. Further, it must be urged that a thorough daylight examination, and overhaul, should be carried out, once every week, and every garage should be provided with a satisfactory, simple, body-lifting gear, so that the chassis may, from time to time, be made ready for a complete, unfettered overhaul. At present, very few omnibus companies have sufficient stand-by vehicles ; but, ultimately, it will be found necessary, considering the large number of hours per day that every bus runs, to have, at least, a stand-by stud of to per cent.
Variety in Coach Fitting and Size of Motorbuses.
Another direction of development, or of evolution, will, I think it quite probable, be the design and construction and working of omnibuses with considerably less seating capacity, and of considerably less total weight. Single-deck omnibuses, and for service, even in this country, through a considerable part of the year, chars-it-bancs, or other numerously-seated, open vehicles, might be used, as they are in so many places on the Continent, especially if the form there common, in which footboards run along each side for use by passengers and conductor, are employed. It is, generally, argued against vehicles of this kind, that the wages of driver and conductor form too large a part of the whole takings of vehicles of such capacity, but I have vet to learn two things on this subject; one, that a penny a mile paid for these wages is greater than 'Id. per mile paid for extra cost of maintenance of heavy vehicles, and, secondly, that there is any Act of Parliament making it necessary for the popular motor vehicle to carry passengers absurdly long distances for a penny. It has, also, yet to be proved to me, that it would not be of very great advantage to be able to stop and start more easily, and, therefore, more readily, for picking up passengers.
The Region of Prophecy.
With regard to the development of the chassis and its machinery, the danger of prophecy is as great as in those earlier matters which have, hitherto, been included in the proverbial saying on the subject. For instance, few who are careful in arriving at a conclusion would like to say much with regard to the oft-repeated question of steam versus the internal-combustion engine for motor omnibuses; though I think that few will agree with the opinion, sometimes ex
pressed, that the internal-combustion motor is not likely to be very much improved, either in thermal or mechanical efficiency, or in its adaptability to the whole of the requirements of the motor omnibus. It is, now, a very few years since the present type of petrol engine was harnessed in the hard, commercial, omnibus field of work, and, already, great improvements have been made in its adaptability to circumstances, in its flexibility and quietness of running, and, in fact, in most particulars, except with regard to simplicity and accessibility. There are some exceptions, even to this, wherein automatic valves are still used, and the whole engine may be, readily, detached from its seating, and its pipe connections may be uncoupled and recoupled in as little time as I am taking to mention the operations. There are some engines, it is true, in which infinite pains have been taken to introduce as many moving parts and connections as could, anyhow, by any number of drawings, be conveyed to the intelligence and perseverance of those who have had to make them ; but the merit of this form of ingenuity has, fortunately, not been discovered by all makers. Judging by the greater number of omnibuses in use, at the present time, it is not, yet, understood that it is possible sa to design the combination known as a chassis, that the whole lot of the machinery could be taken down and re-instated by a small number of men in four or five hours, and that the gear box and its connections may be so arranged that those responsible for the running of omnibuses would feel encouraged to make sure of the satisfactory condition of everything by the taking down and re-instating, which can he done in a couple of hours, rather than to leave things until the unsatisfactory condition is proved, either in the streets, or by finding in the garage, that complete renewal is required where, by better arrangements, a mere adjustment might have sufficed.
Engine Cooling and Disposition.
It is, perhaps, early to expect it, but it does appear to be desirable that the engines should be provided with a cooling system which does not need the aid of a miniature pumping station, or even of a tin, toy fan. It is, also, conceivable that the engine might be so made, connected, and mounted that, in five minutes, all necessary disconnections could he effected, and the engine turned aside, or lifted out of the chassis, for examinations and adjustments, as comfortably as the watchmaker has his watch on his table. It is, further, conceivable that it is not beyond the capability of the designer to carry the engine in the frame, and so to connect the gear box and all the machinery, not only that the inevitable flexure of the frame may occur without twisting crank:. chamber brackets off the chamber, or throwing all sorts of ambiguous stresses on the various parts of machinery and bearings, but so that flexibility in the frame may be recognised, instead of fought against, by unsuccessful attempts at complete rigidity.
Petrol-Electric Systems.
It might be expected that I should say something with reference to the probable future of petrol-electric vehicles; but all that I need say on this subject is, that there is only one system which I have yet seen that commends itself to me as offering any very decided conveniences, or advantages, as compared with the best designs of petrol bus with their present forms of driving gear, and the improvements which I am satisfied will he made in the latter, and the improvements which are already coming forward in the engine itself. Moreover, you have, recently, had a very interesting paper on this subject. Most of the petrol-electric arrangements, which have been proposed, leave it still necessary to have an engine of the full power required for maximum effort, and only substitute electrical generators, and motors, with some drivng gear, for the driving and change-speed gear of the more or less standard systems, whilst they do not decrease weight. One system is to some extent in use, in which an engine of smaller power is sufficient, in which the electrical arrangements do not, materially, increase weight, with which great flexibility and easiness of control is obtainable, and with which it is not necessary to keep the engine running at every time of stoppage. None of the systems have, yet, however, the advantage of any practical trial on the very large scale.
I am afraid that you will think, now, that this paper only satisfies Mr. Esse's title to a very small extent, but the addition to it of a constructive department would take me so long to read, that it would keep you much longer out of your beds than I am inclined to be kept out of mine.