PLATOW'S PATENT AUTOMATON Sir, Our time has been called the "reading," sometimes the "thinking," age, with what truth we must leave to the final judgment of posterity, but if we assumed the simpler title of the "coffee drinking" age, the designation would perhaps be more accurately descriptive of a great and gratifying change in our habits and sentiments, which has doubtless commenced and is rapidly extending, though it may not yet have thoroughly pervaded all classes of society. How different are the feelings with which habits of intemperance are now viewed among our wealthier classes, compared with the toleration and even favour which was conceded to them within some thirty years of our present times! The race of the Squire Westerns of the last century is nearly extinct; their bonhommie would no longer now be admitted in refined society as an apology for their grosser vices. But what is still more gratifying is the commencement of a similar change which is now strikingly visible amongst the very humblest ranks of the community. Voluntary oaths and pledges may perhaps be considered as dubious acts of morality and wisdom. But what great improvement has ever yet occurred in the world's history without some admixture of error, and when were large masses of mankind led to great and wholesome reformation without the powerful aid of enthusiasm, which can only be excited by an appeal to the highest feelings? Feeble, therefore, must that man's judgment be who considers the rash vows which are sometimes (but not always) exacted by societies formed for suppressing the use of intoxicating liquors, as a reason for treating with scepticism or indifference the undoubtedly beneficial results which the advocates of temperance have produced in England and America, and the striking effects which have attended the pure and benevolent efforts we have lately witnessed in Ireland, to rescue the fine but destitute people of that country from the baneful influence of one of the most pernicious symptoms of the degradation and misery in which they have hitherto remained. Among the improvements in the arts connected with these milder stimulants which have in many quarters nearly supplanted the use of ardent spirits, may be mentioned the ingenious discovery referred to and described at the head of this article. The object of this invention is to make good coffee, and clear it by a self-acting process; nothing can be more simple than the operation. The machine consists of two parts: the glass vase, A A, which surmounts the urn, B B, screws off and on by means of the wooden handles, CC, and is furnished with a long narrow and straight_tube (not shown in the drawing) resembling the pipe of a common funnel, and reaching nearly to the bottom of the lower vessel, B B. The following is the method by which the coffee is prepared. Boiling water is poured into the glass vase in quantity sufficient to make the coffee required. The upper vase screws air-tight, by means of a felt washer, and therefore in order to let out the air within the urn, which would otherwise prevent the water from descending, the screw must be slightly relaxed. When the water has gone down, the vase is screwed tight again, and the ground coffee is placed within it, on the perforated silver plate fixed water tight, as shown at dd. Then the lamp, E, (containing spirits or naptha) is lighted and placed under the urn. In a short time steam will be formed on the surface of the water within the urn, and by its elastic pressure will necessarily force the water up the tube before referred to into the upper vase. It will there continue in a state of ebullition, and boil the coffee so long as the heat which generates the steam is kept up; but so soon as the lamp is removed, (which is to be done when the coffee is considered sufficiently boiled) then the steam within the urn instantaneously condenses, by which means a partial vacuum is formed, into which the weight of the atmosphere strains the coffee liquor, first, through the coffee grounds (which are compressed into a cake by the process,) and then through the perforated silver plate. The urn is thus filled with the pure bright and fragrant decoction of the berry, fit for immediate use. The lamp is applied only to the coffee urn in its more ornamental and elaborate shape; a simpler and more common coffee pot may be used for placing on a fire, stove, or gas lamp, in which case the coffee-pot must be removed from the source of heat, so soon as the decoction PLATOW'S PATENT AUTOMATON COFFEE URN. is complete, and the filtering process will then take place as before. Having thus described the mechanical construction and action of this coffeemaking machine, which, from its selfacting principle, is fancifully called the "Automaton," by the inventor; perhaps your readers will not deem a few remarks irrelevant for the purpose of explaining in what manner its peculiar action is supposed to extract from coffee those qualities for which the beverage is distinguished and prized. Coffee when properly prepared is a highly palatable and exhilarating drink. But in England we hardly ever meet with it in perfection. In the small coffee shops frequented by the humbler classes it is a thick, coarse, black, muddy draught of a very uninviting taste and appearance; in most of our inns and hotels it is a liquid of most variable colour, consistency and quality, and even in the dwellings of the wealthy and refined, the art of making good coffee is rarely understood as it is on the Continent. Dr. Donovan, the author of the interesting work on Domestic Chemistry, published in Lardner's Cyclopædia, has proved, that, there are two principles in coffee which may be entirely separated from each other, its aromatic flavour, and its stimulating or medicinal properties, to which are ascribable its agreeable effects on the spirits. Now it is obvious that the art of making good coffee must consist in obtaining a union of these two properties in the highest possible degree. Where great care is used, combined with skill and experience, (for these are as much needed in this apparently simple process as in more ambitious ones!) the object may be attained by the usual mode of boiling. But ignorance will rarely submit to be enlightened, or prejudice to be removed, especially on subjects which appear to be so simple, that an offer of instruction is deemed an officious intermeddling! To Dr. Donovan the decoction of a cup of coffee may appear a nice chemical process, on which even philosophers may have something yet to learn; but to the inexperienced cook, or raw barmaid, this seems a very trifling matter, or at all events, it must be left to their sovereign and exclusive control! Now the great advantage of Mr. Platow's invention is, that in the making coffee the services of these fair and amiable, 435 but not always very tractable ministrants are dispensed with! The "Automaton Coffee Pot," as the name imports, does its work without the aid either of the fair or the less worthy sex! In truth, it is a little steam-engine. The following may be enumerated as the characteristic benefits of this invention : 1. Owing to the rapidity with which the coffee is extracted by the means above described, the medicinal or stimulating quality of the berry is obtained and the aroma is also preserved. 2. The coffee is always of a clear and bright amber colour and does not require fining. 3. The result, depending as it does, on unerring physical laws is, and must be uniform, and the coffee can never be spoiled by the unskilfulness or carelessness of servants. To compare small things to great, the "Automaton Coffee Pot" is to coffee-making what Humphry Potter's accidental discovery was to the steam-engine. The most skilful engineer could not adjust the supply of steam with the same accuracy as the self-acting valves, and the most careful preparer of coffee (according to the old method) will generally find himself beaten by the self action of Mr. Platow's improvement. Having said so much of the "philosophy" of the "Automaton Coffee Pot," (for which I owe an apology to your fair readers, to whose province the invention especially pertains!) let me add a few words on its lighter attractions. These are by no means to be overlooked even with reference to the solid ends of practical utility. Coffee, when extracted according to the operations generally received cannot be agreeably or conveniently made in the parlour; it must be left to the fair Hebes before alluded to! But Mr. Platow's improvement (in consequence of the simplicity of the principle on which it acts) enables the lady of the house to make coffee with her own hands without the aid or interference of servants. Hence the apparatus is generally so constructed as to render it ornamental, and the process of extraction which is distinctly visible through the glass vase, has a pretty and agreeable effect, not unsuitable to the breakfast table or the drawing-room of the most refined. A short time after the lamp has been applied, the hot water is seen rising suddenly into the glass vase bubbling and swelling like a hot fountain in minature. But no sooner is the lamp withdrawn, than the current is reversed, and the filtered coffee appears running down into the urn in a rich transparent stream. These abrupt transitions in the process and the rapidity with which the coffee is obtained in perfection, make "the Automaton" and its exploits a subject of interest and amuzement—a pleasing toy alike to the philosopher and the child! Your obedient servant, SINBAD. ON LONG AND SHORT STROKE STEAM ENGINES. Sir, My attention has been frequently turned to a subject of some importance, and one which has been the occasion of much talk, but which in my opinion has seldom been discussed upon correct grounds; and as I am not aware that it has been investigated in your valuable journal, perhaps you will allow me to invite some of your correspondents who are engineers, or who are otherwise interested in the matter, to thoroughly examine and decide beyond any further dispute the question at issue; which is—what proportion should the length of the cylinder of a steam-engine bear to its diameter? The comparative merit of long and short"strokes" has been a matter of much speculation among engine builders, scarcely any two of whom agree as to the best proportions of a cylinder, and few of whom it is to be feared ever take the trouble to go into an accurate calculation of the useful effect produced by cylinders of equal cubical capacity, but of different proportions-they are rather guided by experience and observation, both of which it is allowed are indispensible requisites in an engineer, but neither of which in the present case can prove either the one fact or the other; and as the question certainly is one which admits of mathematical demonstration, an appeal should at once be made to so impartial and unerring an umpire. Singular as it may appear, the greatest disparity exists upon this point among engineers of the highest rank-those who build marine engines, in which the smallest change for better or for worse is in the end attended with important results. It is well known that American engineers have for several years been gradually adding to the stroke of their marine engines until they have reached the enormous length of eleven feet and upwards. English engineers on the contrary, have been constantly reducing the length of their cylinders from the proportion originally assigned by Watt, until it is rare to see a marine cylinder whose diameter is not greater than the length of the stroke. For anything like an exposition of the causes which have led English and American engineers into such opposite extremes-extremes too, which are every day becoming wider, I have looked in vain-Mr. Stephenson's work,*although containing the fullest and most correct account of this branch of American engineering yet published, fails to assign any adequate reason for using cylinders of such extraordinary length. As an American, however, I cannot but admire the candour and impartiality which pervades this book. Even in the instance just alluded to, his attempt at an expla nation seems to have been in some measure intended as an apology for one of Jonathan's "notions," which it is evident he could not clearly see through; but while looking in vain for a satisfactory motive which he might attribute to American engineers for giving their engines such proportions as have always looked strange to English eyes, he gave that which seemed to be the most plausible. He seems, however, to be a long stroke man, and evidently approves of long cylinders wherever he thinks them admissible, as in the case of the American river boats, and like many others, attributes the short stroke of the English engines to the necessity of keeping them below deck, in consequence of the exposure of English boats to heavy weather. Now, if long cylinders possess any advantages over short ones for river navigation, I see no reason why they do not possess equal advantages for sea-going vessels-neither do I see any obstacle to the introduction of cylinders of any required length into such vessels whenever it shall appear that increased length is *Sketch of the Civil Engineering in North America, by David Stephenson, Civil Engineer. London: John Weale. WIRE ROPES FOR MINING PURPOSES. desirable. The U. S. steam frigate Fulton, a vessel of only 800 tons, is fitted with engines of eight feet stroke, and yet her works are entirely below deck. If increased length of stroke be desirable, why not at least adopt it on board of the Thames river steamers. Mr. Stephenson's explanations seem the less satisfactory, since he has quite overlooked the fact, that while the American boats upon the unrippled surface of the Western waters are worked by horizontal engines, snugly stowed and not remarkable for their length, those upon Long Island Sound, which are partially exposed to the sea, and occasionally encounter very heavy weather are worked by engines with a stroke of from ten to twelve feet; while the boats which ply between the city of Boston and the various ports "down east," over a tract of sea coast, which for boisterous weather is second only to Cape Hatteras, are propelled by engines of a still greater proportionate length; and although light boats, have long been known for the regularity of their passages. From these data, then, it would seem that neither Mr. S. or any of his predecessors have succeeded in throwing much light upon the point in question; for it appears, that in proportion to the degree of exposure to be encountered by American boats had been the increase in the length of their engines. It is also a fact well known to travellers, that the best and steadiest sea boats upon the American coast, are those which have the upper works of their engines considerably elevated above the deck, and their boilers upon the guards, and it is not improbable, that whenever Jonathan gets money enough to send sea-going vessels to foreign ports-the first object to be descried at sea will be the beam of the engine half way up to the mast head. The opinion entertained by Mr. S., that an increased length of stroke enables the engine, when working singly, to pass the centres with greater certainty, is entirely without support; for the piston, piston-rod, and connecting rod, however heavy, and although moving at an increased velocity, cannot, by their inertia, contribute in the slightest degree to assist the engine over the centres; besides which, the wheels of the American boats are generally so large and heavy, and move at such a velocity, as to render any further aid superfluous. 437 Prof. Renwick, of New York, in his paper on American Steam Navigation, contained in Tredgold's work, seems to have been aware that his English readers would expect some explanation in relation to one of the most remarkable peculiarities of the American boats; but, unfortunately, in his eagerness to attribute the speed of those boats to the use of long cylinders, he has fallen into an error of the grossest kind, for which he will get few thanks from American engineers, who may well exclaim "Save us from our friends!" The Professor has mounted the old hobby so often ridden -that of gaining power by increased leverage, or, as it is often termed, " causing the steam to act at a more favourable point." A blunder like this now-a-days from a Professor is not deserving of correction. Enough has been said, I think, to show that long or short cylinders have very little to do with the seaworthiness of a vessel, and that American engines have been lengthened or English engines shortened for reasons which have not been sufficiently explained; indeed they cannot be fully apparent so long as our only data is derived from statements put forth in the heat of rivalry by parties who are ready to go all lengths in support of a favourite or preconceived theory. Trusting, however, that a careful consideration, upon correct principles. of the question previously proposed, will open the eyes of all who are not wilfully blind, I, for the present, leave the subject in abler hands. I have the honor to be, Sir, WIRE ROPES FOR MINING PURPOSES. Sir,-In compliance, with a request for information with respect to wire ropes, expressed in a letter signed "E.," in No. 864 of the Mechanics' Magazine, I may mention, that Count Brenner in appropriating to his countrymen the invention of wire rope and its application to practical purposes, has been guilty (perhaps unknowingly) of injustice, provided it was not so applied in Austria, more than five years ago. Sir, about this period Mr. Smith, engineer, Princesstreet, Leicester-square, took out a patent |