The next objection taken by Dr. Lardner is, that the upper parts of the water chambers are liable to early destruction from containing no water. On this point we would individually merely observe, that these parts are so far removed from the intense action of the fire, as not to be liable to early injury from that cause, and that the advantage of increasing the elasticity of the steam by the waste heat before it enters the chimney, more than compensates for the slightly increased oxidation that the metal may sustain from the heated air. Dr. Lardner, however, so far from admitting that there is any advantage in heating the steam, insists that there is a positive loss ; these are his words • " It has been observed by engineers, and usually shown by experiment, that if steam be heated on the surface of the water, it will be decomposed, and its elasticity destroyed." Where can that engineer be found, and where may that experiment be seen ? We venture to assert that the former has no name, and the latter no place. We need not stop to discuss this point, as our scientific readers well now that the statement is directly at variance with all reason and theory ; and we know from experience, that it VI equally at variance with practice. 1% e have repeatedly applied a lighted brand to the steam chamber of a tubular boiler, when the engine to which it was attached was working sluggishly, and the result has uniformly been, such a sudden accession of force as to cause the engine to go off' with impetuous violence. It was once a prevalent opinion, that the reheating of steam, so as to raise its temperature to the same degree as it would have acquired by heating the water alone, would have the effect of communicating to it a similar degree of elasticity ; but those who tried it, being disappointed by finding the reality fall so far short of their high expectations, it was entirely overlooked by them ; hence the unreflecting ran into the opposite extreme, some saying there was no advantage, and others that there was a loss ; a loss of elasticity by the interposition of caloric 1 We shall, however, close our remarks on this point by reference to the opinion of Mr. John Farey, who requires no additions to his name to distinguish him as the highest authority in this country on such subjects as the present. In his evidence before the Select Committee of the House of Commons on steam carriages, at page 42, he says, " Mr. Hancock has taken the middle course in subdividing the water in his boiler, having all that can be required for safety ; and the weight, on the whole, I believe to having less than that of any other boiler which will produce the same power of steam ; for, owing to the freedom with which the steam can get away m bubbles from the water, without carrying the water with it, the surface of the heated metal is never left without water. Hence a greater effect of boiling is attained from a given surface of metal and body of contained water, and that with a much greater durability of the metal plates, than I think will ever be obtained with small tubes." Mr. Hancock being satisfied that he had obtained in this boiler the requisite means of generating adequate power, turned his attention to the various arrangements of the carriage and propelling machinery. His first carriage was constructed uponthree wheels, and the power was applied through the medium of two vibrating engines fixed upon the crank axle of the fore wheel. The direct application of the power to the crank by this method, gave him ardent bopes of success ; and three wheels have the unquestionable advantage of greater facility in steering. After many trials, however, and various alterations, experience proved that it was attended with so many " practical drawbacks," that it was finally abandoned. After this, Mr. Hancock devoted much time to the construction of a propelling apparatus, under the idea that TM so pertinaciously inculcated by writers (in spite of the experience to the con trary by railway engineers) that " the bite' of plain wheels upon the common road was insufilcent to propel ; but experience proved to him also, the utter uselessness of any such adjuncts as propellers, as they were distinctively termed ; and he moreover found, in his first carriage, that the single fore wheel alone was fully adequate to perform that office.
Defective as this first carriage must necessarily have been, Mr. Hancock states in a memoir that he has had the kindness to transmit to us, that it ran many hundred miles in experimental tripe from the writer's manufactory at Stratford, sometimes to Epping Forest, at other' to Paddington, and frequently to Whitechapel. On one occasion it ran to Hounslow, and on another to Croydon. In every instance it accomplished the task assigned to it, and returned to Stratford on the same day on which it set out. Some of the experi ments we personally witnessed.
Subsequently, this carriage went from Stratford, through Pentonville, to Turnham Green, over Hammersmith Bridge, and thence to Fulham. In that neighbourhood it remained several days, and made a number of excursions in different directions, for the gratification of some of the writer's friend., and others who had expressed a desire to witness its performance. In the course of these early experimental trips, Mr. Hancock experienced the usual fate of all who run counter to long standing usages and prejudices ; namely, to be ridiculed by the many, encouraged by but a few, and fiercely opposed by all whose personal interests were threatened with injury by his proceedings. Some would admit frankly that the carriage worked well; but expressed their decided conviction that it would never answer for a continuance. Others would depreciate its performances, exaggerate its defects, and exult, as it were, in every instance of accidental stoppage. If requiring temporary accommodation, through the failure of some part of the machinery, a circumstance naturally enough of fre quent occurrence in this early period of his locomotive career, Mr.Rancock usually experienced the reverse of kind or considerate treatment. Exorbitant charges were made for the most trifling services, and important facilities with held, which it would have cost nothing to afford. If temporarily detained on the road from the want of water, or from any other cause, he was assailed with hooting, yelling, hissing, and sometimes even with the grossest abuse; wag gons, carts, coaches, vans, trucks, horsemen, and pedestrians, pressed so close on the carriage, as sometimes to preclude the possibility of moving; and his situation was often rendered very irksome and irritating ; sometimes very hazardous. Undismayed by these untoward circumstances; however, he perse
vered in his experiments ; and as the novelty of such exhibitions wore off, so did the excitement and the opposition which they at first produced.
Becoming convinced prom experience that there was a disadvantage in applying the power directly to the crank, as before noticed, Mr. Hancock next placed the engines quite behind, and at the same time altered the form of the carriage, so as to make it more nearly resemble an ordinary horse carriage. Much study and labour were spent upon the various alterations that were suggested and tried from time to time. But the difficulty of keeping the machinery clean, owing to its proximity to the fireplace, as well as to the road, was found in practice to be so strong an objection, that this form of carriage was also abandoned. Nevertheless with this carriage, one point, of the greatest import ance in steam travelling, was most satisfactorily determined. The possibility of a steam carriage ascending steep hills had been doubted and questioned by many; and to remove, if possible, all scepticism on the subject, a day was appointed for taking his carriage up Pentonville-hill, which had a rise of 1 in 18 to 20, and a numerous party assembled to witness the experiment. A severe frost succeeding a shower of sleet, had completely glazed the road, so that horses could scarcely keep their footing. The carriage, however, without the aid of propellers, or any other such appendage, ascended the hill at consi derable speed, and its summit was attained, while his competitors, with their horses, were yet but a little way from the bottom. Stimulated by the suc cess of such experiments, he remodelled the entire arrangement of the' machinery. The trunnion engines were laid aside, and fixed ones substituted ; and such other alterations and improvements adopted, as had suggested them selves during actual work upon the road. The carriage, as thus reconstructed, was called, in reference to the infancy of the undertaking, the " INFANT." In this engine, the bulk of the machinery is fixed in the rear of the part appro priated to the passengers. There is, first, the boiler, with the fire-place under it. Second, a space between the boiler and passengers, for the engines, and the engineer who accompanies the carriage, whence he has the whole of the machinery within his reach, and open to his view; and is thus enabled, during the progress of the carriage, to lubricate the parts requiring oilattend to the gauge-cocks, and regulate the supply of water to the boiler, as well as the degree of blast from the blower—to increase or diminish the generation of steam, according to the various states of the road, and the wants of the engines, —and generally to give his immediate attention to any portion of the machinery' requiring adjustment. And, third, a pair of inverted fixed engines, working' vertically a crank shaft. The whole is on one framing, supported by four common coach springs, on the axle of each wheeL On the crank shaft and on the axle of the hind wheels, are fixed indented pul leys, around which an endless chain passes, which communicates the power and ro ta/ motion of the crank shaft to the hind axle, and propelling wheels, and there effects the progressive motion of the whole carriage. When it is des' to back the carriage, the action of the engines is merely reversed, which can be effected almost instantly. The advantages realised by the improved arrangement shown in the Infant are numerous. The engines are completely protected from the dirt and dust of the roads ; are at all times in sight of the engineer, and every part of them is with/I-his reach. The passengers, engines, boiler, fire-place, &c., are all equally xelieved from concussion, by complete sus pension on springs, similar to a stage coach ; the chains allowing full play to the springs, and a vibrating stay from the crank to the axle preventing the pull of the chains, and securing a uniform distance between the axle and crank shaft. By the employment, too, of a distinct crank shaft, the axletree, which has to carry all the weight, is not only preserved straight, and consequently of the beet form to sustain that weight, but it is also relieved from the strain which it has to bear, where it forms both crank and axle, and has to propel the car riage, and carry the weight as well. The Infant thus fitted up, was tried in every possible way, during several months, and proved so perfectly efficient, that in all the carriages which Mr. Hancock has since constructed, he has adhered to the same general plan of arrangement, with the exception of some modifications in the details, which more extended experience has suggested. But though the general arrangement of the Infant was such as to leave but little occasion for alteration, there were yet several important points that remained to be cleared up, such as the best proportions and size for the chambers of the boiler— the best form for each separate portion of the machinery—the proper position, size, and strength of the various parts, and also the most suitable kind of mate rials, so as to avoid as much as possible superfluous weight Experiments to ascertain these various points occupied Mr. Hancock till the beginning of the year 1931, so that full six years had elapsed from the commencement of his locomotive pursuits, before the Infant was produced in a state somewhat to the satisfaction of his own mind. The trials made during this probationary period, comprise a total of many hundred miles, all made upon the high roads, near London, principally in the vicinity of Stratford ; between which place and Whitechapel, vehicles of every description being in constant motion, afforded him an excellent opportunity of obtaining practical experience, under every cir cumstance of difficulty, in which a steam-carriage might be expected to be placed • and this consideration determined him to give the most frequented road the preference. In February, 1831, he commenced running the Infant regu larly for hire, on the road between Stratford and London; not, certainly, with an anticipation of profit, but as a means of dissipating any remaining prejudices, and establishing a favourable judgment in the public mind as to the practica bility of steam travelling on common roads. Mr. Hancock observes, that it is an undeniable fact, and a source of proud satisfaction to him, that a steam car riage of his construction was the first that ever plied for hire on a common road, and that he achieved this triumph single-handed.