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96 THE CIVIL ENGINEER AND ARCHITECT’S JOURNAL. [March, others, but made him dependent on himself; and this confidence was rarely in vain, for his errors were always less those of judgment than consequent upon a hastiness of disposition, which, as it had met with but little sympathy from the world, was but too apt to despise it. His skill in providing for all occurrences was rarely baffled, and could not easily be surpassed, while his original and gigantic conceptions, how ever much beyond the progress of his age, were seldom beyond the bounds of ultimate practicability. That his name is but slightly known, and his labours consequently little appreciated, is by no means a result of their unimportance, but the effect of concurrent circumstances, which, as they can elevate in significance, too often obscure merit. When lie had conceived a plan by the resources of his mind, and confirmed it by experiment, the very vastness of it surpassed his means of execution, and prevented it from being carried into effect. He was himself no financier, and the asso ciations he formed with Vivian and others were either insufficient in their extent, or turned more to the profit of Ins colleagues than himself. It was true that he left no means unsought of obtaining the assistance of others, but those who had capital feared to engage in enterprises to which they were unaccustomed, while those used to business had no disposition to deviate from the track in which they were long practised and successful. It is the nature, indeed, of great monopolies, that their very success engenders want of activity', for none feel so little in clination to engage in new processes as those who are accumulating wealth by old ones. It is this that deadens the progress of the iron trade, of distilling, and many others ; and the manufacturers, instead of supporting new inventions, spurn them as associates, and trample them down as rivals. It was the support of this influence which gave power to Watt, while it cramped the energies of Trevithick ; for without the aid of Boulton, the former might have wasted his life in experiments, or, Hargrave-like, have been supplanted by another Arkwright. Tre vithick wanted but this to compete with Watt in worldly prosperity, and he wants not this to equal him in the height of his genius, the greatness of his w r orks, or the wide-extending influence of his inventions. That the memory of Trevithick has not received the honours which have been conferred upon others, is a neglect which has been shown to many of our greatest names, and proceeds less from our want of venera tion for men of genius than from our national character. We do not, like Frenchmen, dread a rival near the throne, nor are we, like Ameri cans, fearful of others denying to us what we are scarcely known to possess. We are rich enough in illustrious names to consider their admission in our domestic habits and our thoughts as a sufficient sacri fice to fame, and it is only on the instigation of some provincial that we raise statues to those who live in our hearts. Our population in the north, however, less fertile in their contributions to the shrine of genius, and more, remarkable for local preference than extended sym pathies, give a greater share of admiration to the few of whom they dare to boast. The English, in acceding to their suggestions, while they commemorate inferior names, create mementos of their own neglect. While, therefore, there are three memorials of Walter Scott to one of Shakspeare, and to Milton none, we must not consider the many tri butes to Watt as emblems of superiority, but as proofs of a better fate. It is to this that we must attribute that a statue is rising to Watt in Manchester, while Brindley’s merit still relies upon the glorious memory of his canal. We may carry, however, this self-confidence too far, and where we meant only to show hospitality, may have brought in strangers to master our own children ; when we see the generosity of the American Congress to the spurious claims of Fulton, and the gratitude of Peru for the labours of Trevithick, we are called upon to offer some honour to his name, and to show that we are as proud of the inventor of the high-pressure machinery as wc are conscious of the benefits we derive from his railway locomotives. But, neglect him as we may, the name of Trevithick will live while his engines annihilate space in the Old World, and in the New control the current of the Mississippi, and disgorge the mountain riches of the Cordilleras. MR. OLDHAM’S SYSTEM OF WARMING AND VENTILATING, AS ADOPTED AT THE BANK. OP ENGLAND AND BANK OP IRELAND. Sir,— As the best mode of heating and ventilating apartments and buildings is still an undecided matter among scientific men, I avail myself of your journal to draw public attention to what appears to me to be the best among the various plans and patents of the present day. At a late meeting of the Royal Institution, Professor Brande, in the course of his Lectures on Heat, and in considering its transmission and diffusion by means of currents, pointed out the advantage of aiding the operation of those currents by mechanical means. In illustrating this mode of conveying heat where extensive apart ments are to be acted on, and where either a large volume of air or a great quantity of heat may be required, the Professor described the operation and effect of an apparatus successfully adopted by Mr. Old- barn, of the Bank of England, in which building it has been in use during two years, having previously been adopted by him in the Bank of Ireland, and where it has been in operation during sixteen years. When heat is conveyed by means of natural currents, these are necessarily, and exclusively, due to the difference in the temperature and specific gravity of the column of air, when heated, relatively with that of the surrounding atmosphere ; the force of these currents, and the body of heat they are enabled to transmit, are therefore necessarily languid, compared to what may be effected by artificial means. That steam is the best medium for the transmission of heat is now too well known to require much illustration. Its superiority over water (independently of the greater facility with which steam is con veyed to a distance) is derived from the extraordinary quantity of heat which water contains when in the state of vapour—a cubic foot of water, in the form of vapour, having the power of giving out nearly eleven times more heat, than the same body of water could when in its liquid state. The mode hitherto adopted in many establishments, and in the large cotton-factories, is that of conveying steam through a continuous series of cast-iron pipes, so arranged and extended, through the several apartments to he heated, that each shall be supplied with a given length and surface of pipe, proportioned to the dimensions of the apartments to be heated. This is manifestly a mode attended with great inconvenience and expense in the conveyance of such pipes, in their liability to leak; and in the want of uniformity in the temperature of the several parts of the rooms in which those pipes are introduced. But there is yet another and more formidable evil attending this mode of heating, namely, that while it merely conveys heat to the already existiug air in the chambers to be heated, it has no relation to the condition of that air, or the supply that may be required, or the changing and purifying the same. In a word, the system, by means of steam-pipes, has the power of heating, but not of ventilating. It has no relation to the purity or impurity of the air to which it imparts the heat; and it is a fact, that giving an additional supply of heat to an apartment may even be prejudicial, inasmuch as such apartment may require ventila tion, that is, change of air, rather than heat. Now the process of heating adopted by Mr. Oldham has this peculiar and distinguishing characteristic, which gives it a claim above all others, namely, that it botli heats and ventilates at the same time, to any extent, and with any required rapidity. As far as health and comfort are concerned, heating and ventilation should never he separated. Mr. Oldham’s process and apparatus most effectually supplies this desideratum. Doctor Ure, in his inquiry into the modes of warming and ventilating, observes, that “ the great principle of ventilation is, never to present the same portion of air twice over to the human lungs, but to supply them at each fresh inspiration with pure aerial particles in a genial thermometric and bygrometric condition.” Where heating is alone attended to, as in the case of heat conveyed, by steam in metal pipes, it becomes necessary to provide currents of cold air, to supply the required continued change in the apartments for the purposes of ventilation. It is manifest, then, that the best principle must be, first, to heat the required volume of fresh air, and then introduce it to the apartments to be heated and ventilated, instead of effecting this double object by two distinct processes. This is ’ effectually accomplished by the plan of Mr. Oldham under consideration. ’Die modus operandi is as follows :—A body of pure air, of any required volume, and passing at any required velocity, is forced by the aid of an air-condensing pump into a chamber or chest, where it is heated in an ingeniously-contrived, but extremely simple apparatus, by means of cross currents of steam. The peculiarity of this contrivance is, that an ascending body of air, on entering this chest, divides itself spontaneously into any required number of thin horizontal films, by which a very extended surface is exposed to corresponding steam-heated metal sur faces. Instead, therefore, of passing the steam through a series of pipes, along which, but in an opposite direction, the condensed water has to return, it is conveyed at once from the boiler iirto the chest orcondenser, (which, in fact, it is,) where, on having parted with its heat to the air as above described, it is condensed, and returned directly to the boiler. The chest or condenser, in the apparatus at the Bank of England, is but three feet square, yet the body of air to be heated, while passing over but 3 lineal feet, spreads itself over no less than 1.54 superficial feet, and coming in contact with a corresponding superficies, heated by the steam, it necessarily receives a very large supply of heat in a short space of time.
