ROWLEY'S ROTARY STEAM-ENGINE. Manchester, 14, Upper Brook-street, August 2, 1842. Sir,-The little success which has hitherto attended rotary steam-engines has caused most people to be sceptical as to their ever being able to compete in efficiency, economy, and durability, with reciprocating ones. Influenced by this, I resolved not to publish any statements regarding the one patented by me, till it had worked for such a length of time as would enable me to speak confidently as to its performances. I have now pleasure in forwarding you, for insertion in your very interesting publication, accounts of the stationary engine belonging to Messrs. R. Johnson and Brother; and also of a locomotive, on the same plan, which has been experimented with on the Liverpool Railway. I have the honour to be, sir, Your very obedient servant, I. The Stationary Engine. Diameter of steam-wheel, 36 inches; breadth of ditto, 14 inches; depth of ditto, 4 inches; mean length of steam chamber, 100 inches; pistons or slides, 58 square inches, subjected to the action of steam; number of revolutions, 80 per minute; with 1 lb. pressure ungeared, or with less than 5 lbs. driving shafting. It stands on a bed-plate, 5 feet by 4, and is 34 feet high. By reference to the figures 1, 2, and 3, it will be seen that the engine is composed of an outer ring, or cylinder, A A A, and two side plates, exactly alike, having on their inner side an endless groove, B B B, formed of a segment of a circle, a a a, and a portion of an irregular curve, bb b. There is a circular wheel or apparatus, C C C, having three chambers, D D D, in it, for the reception of the pistons E E E, and for allowing the same to slide in and out. This wheel has two flanches, G G G, having grooves in them, H H, for the support of the pistons, and is firmly keyed on the central shaft F F, which passes through the side plates, and revolves in suitable bearings. The guide-pins of the pistons, K K K, travel in the endless groove BBB, on the inner side of the side plates. Thus it will be seen, that, as the expansive power of the steam, introduced through the inlet pipe L, exerts itself against the pistons, it will cause the wheel C C to revolve; and as the guidepins of the pistons travel in the endless groove B B, the pistons will be alternately drawn towards the centre of the wheel, to enable them to pass the abutment M M, and then be again projected into the steam-chamber; after the steam has exerted its force against the pistons, it will escape by the exit-pipe N. 00 denotes the chamber for metallic abutment packings. The engine is employed in turning wire, or rather ripping blocks; and as the force which is exerted is constantly varying, (the mercurial gauge attached to the cylinder ranging from 5 lbs. to 35 lbs.) it is difficult to estimate the horse power actually used. To calculate the power, multiply the number of square inches on the piston, 58, by the pressure, 30 lbs., and that by mean length of steam chamber, 8:4 feet, which multiply by number of revolutions per minute, 80; then dividing by 33.000 will give the horse power. = Thus, 58 x 30 x 84 x 80 ÷ 33.000 354 horse power. Messrs. R. Johnson and Brother have permitted the publishing of the following letters. ་་ "Wire Mill, 27, Dale-street, Manchester, "August 14, 1842. "Mr. E. B. Rowley. "Sir,-We have great pleasure in stating that we are perfectly satisfied with the regularity of working of the rotary steam-engine. The consumption of fuel, and time worked during the five weeks ending July 29th last, are as follows-338 hours time, and 48 tons 10 cwt. of coal. The engine has been at work on our premises for the last seventeen months. "We are, &c. &c." "This is to certify, that I have had the management of Mr. Rowley's Patent Rotary Engine for the last eleven months, and testify that it works remarkably well and powerfully. The engine has been lately examined, and found in excellent condition. "WILLIAM AMPHLETT, Engineer, "At Messrs. R. Johnson and Brother." "August 5, 1842." II. The Rotary Locomotive. The best method of arrangement must be decided by experiment. I am at pre cranks, and an intermediate shaft having a spur-wheel on its centre, which works in a pinion on the driving axle. The advantages that will result from this are, that the same engine may be adapted for a passenger or luggage train; or, in other words, can be made equal to a 11 or 18 inch cylinder, by proportioning the spur gearing. There will also be an entire absence of any sinuous or oscillatory motion, which is a fruitful source of danger, is highly destructive to the tires of the wheels, and has a constant tendency to disturb and damage the rails, The experimental locomotive recently tried on the Liverpool line was driven by spur-gearing on the centre of the driving-axle, but differently arranged from the plan now proposed. As respects its friction, it was found that with 2 lbs. pressure in the boiler, when the drivingwheels were supported, it would make 80 or 100 revolutions per minute, and that with 10 lbs. it would move itself and tender on the rails. The highest velocity obtained was 37 miles per hour. The following are the results of some of the experiments, though I must premise, that the boiler used was an old and inefficient one. The dimensions of its heating surfaces are 37 84 square feet, exposed to radiant caloric; 258:44 feet are of tube surface; length of ditto, 6 feet 6 inches. measurement of the water in the tender, at starting and at stopping. From the leaky state of the boiler, and from an imperfection in the reversing valve, which was not tight, one-fifth of the whole quantity of steam generated was wasted. The water was nearly cold in the tender at starting. I think the result of the experiment very fair, upon the whole; and I feel satisfied that, with an efficient boiler, the engine will be found both economical and effective. One of its great advantages is, that there is no lateral motion. As I have made many trips with the engine, I can state that the sinuous motion which takes place in the ordinary form of the locomotives in use does not happen with your engine, thus rendering it less likely to run off or injure the rails. The pressure of the steam in the boiler was ascertained by a thermometer, and also by two safety-valves, with the usual spring balance. I took the pressure at the end of every mile. "Yours very truly, "MONTAGUE L. PHILLIPS." Sec. Pressure in Boiler. 1 46 run in t. cwt. qrs. miles. 57 4 25 14 As an accurate account of the consumption of coke had not been kept, a trip was made to ascertain this: the following are the particulars, as furnished by Professor Phillips, of the New College, Manchester. "Manchester, Monday, July 18, 1842. "Dear Sir,-I enclose the following account of the experiment made with the Mars rotary locomotive engine, on Saturday last, to determine the consumption of fuel. I should first state that the boiler was so imperfect and leaky, that we dared not put any pressure on, so that the actual power and velocity of the engine with its load could not be fairly tested. All the tubes were leaky, and several plugged. "At the mean pressure of 40 lbs. per square inch in the boiler, the engine would have consumed 5141 gallons of water during the experiment; whereas the quantity actually employed was 617 gallons, by actual 7 38 20 30 47 34 41 56 33 30 31 36 38 44 38 36 30 54 40 41 50 42 47 34 PROBLEM IN TRIGONOMETRY. Sir, I am rather late in enrolling myself as a contributor to your very useful and widely circulated miscellany; but papers of an interesting and novel character having accumulated on my hands, I hope that you will, from time to time, allow me a small space in your columns, in order that I may communicate their contents to the public. Some of those papers are of a very abstruse and startling nature, and may probably excite some curiosity in the minds of many of your readers; others are of a nature purely practical, and will be read with interest by those who are engaged in mechanical pursuits. As my name is already well known in connexion with mathematical and mechanical subjects; I feel inclined to have it suppressed in all my communications, and propose to pass incognito, under the anagrammatical designation of Your friend and Servant, There is a problem in Trigonometry of very great use to maritime surveyors, in fixing the position of rocks, shoals, and other dangerous obstructions to navigation. This problem has been very often proposed for solution, and as often resolved, but there is still wanting a practical rule that will apply to all the cases, without requiring a separate investigation of a different construction for each. In one of the early numbers of Mr. Colburn's United Service Journal, I gave an analytical solution of all the cases, deduced from a valuable but neglected theorem in Emerson's Trigonometry. This solution, with slight variations, was shortly afterwards copied into the third volume of Dr. Hutton's Mathematical Course, but without any acknowledgment of the source from which it had been obtained. The several equations arising from the solution here alluded to have all more or PROBLEM. Given the distance between two objects A and B, with the angles observed at the stations C and D, (all in the same plane,) to find the position of the stations. My attention was first directed to the subject by Captain John Hobbes of the Royal Engineers; while he was superintending the grand trigonometrical survey of Ayrshire, in the West of Scotland. The solution I then gave was purely geometrical: but it was considered by the proposer, and other mathematicians in that part of the country, as being a very comprehensive and elegant one, and gave occasion for much discussion amongst those who were capable of appreciating its beauties. It is not unlikely that a republication of the problem, may elicit an answer from some of those who remember the circumstance, although a period of more than twenty years has elapsed since it was first agitated amongst them. U.S. August 19, 1842. TRANSMISSION OF GALVANIC ELECTRICITY MESSRS. WRIGHT AND BAIN'S EXPERIMENTS. Sir,-In your Magazine of the 23rd ult., is a letter signed "C. W." in which the writer has called attention to some successful experiments made at Calais in 1803, by passing galvanic electricity, when using water as part of the electric circuit, in order to show that Mr. Bain and myself were not the original discoverers of the two or three facts you mentioned, as having witnessed at the Serpentine river. Neither Mr. Bain nor myself were aware of similar experiments having been tried by Aldini until we saw "C. W.'s." letter; but, if we had been, they were not exactly analogous to ours, as it appears he used a "pile of eighty plates," which would produce an electri |