Expanded Steam. Messrs. Editors:—In your issue of May 15th, your correspondent from Keokuk further criticises the cards published by the Wood & Mann Steam Engine Company, and conveys the idea that the engine at Elmira he refers to was one of the same class of engine built by this company. This company have never sold any engines at that point, and from his description he could not have referred to a Corliss Engine, or any other first-class cut-off, and the one he speaks of was undoubtedly some engine claimed as a cut-off; but we will venture the assertion that were the facts thoroughly understood it would be found to be a puppet-valve engine, or some other throttling valve gear, imperfectly made, and proportioned with insufficient fly wheel, and also to have other serious defects, such as no first-class builder understanding cut-off engines would have adopted. It seems we failed to get at the precise meaning of his previous article, and it suggests the importance, especially on subjects of a scientific nature, of carefully measuring the signification of words used in discussion. When your correspondent wrote, " No such card could have been taken irom any engine," he referred, it appears, to the deductions made from the card, and not to the card itself. The correctness of the deductions we are prepared to maintain, but can only reiterate the statements we have already made. Why steam at 60 lbs., expanding 16 times, showed 3 lbs. terminal pressure on that card was owing to re-evaporation and to leakage of steam valve. That kind of valve has, on that account, since been discarded, and a Corliss valve substituted. The indicator does not gage the actual amount of steam used, for it does not in whole or part register the loss due to condensation, leakage, etc. Of these it takes no note, but it does give an insight into the working condition of an engine obtainable in no other way. One point your correspondent makes is this: When the steam valve opens after the piston begins its forward movement, why does the entering steam line on a card fall forward, compression having apparently ceased ? This I cannot explain, but believe negative lead always produces that effect on a diagram. Perhaps some of your readers, familiar with indicator cards can explain why. Regarding the relative value of the " country engine," and the " short cut-off'," it seems to us that any theory, after long years of practical success, ceases to be a theory, and becomes an established fact. ? We humbly submit that the practical value of highly expanded steam as a motor, is, in 1869, an established fact. HOWARD ROGERS. Utica, N. Y. The Use in Conjunction of Boilers of Different Sizes and Patterns. MESSRS. EDITORS It is often the case that toilers of different sizes arid patterns are used together, and being set on same level is always thought sufficient to secure a uniform hight of water in them. I have two tubular boilers of different patterns to generate steam for a stationary engine. They are connected together in the steam room by a two-inch pipe and in the water space at bottom of firebox by another pipe. There has always been considerable trouble in keeping the same level of water, or rather a proper level, in both boilers. The boilers are of the following dimensions : No. 1. Firebox surface 80 feet; flue surface 513 feet; grate surface 12'3 feet ; contents of boiler exclusiva of flues and internal firebox 67'8 cubic feet; thus giving somewhat over seven feet of heating surface to one of capacity. No 2. Firebox surface 75 feet; flue surface 458 feet; grate surface 10'8 feet. Contents of boiler exclusive as above, 1093 cubic feet, being not quite five feet of heating surface to one of capacity. No. 2 was fed by a pump attached to stationary engine. No. 1 had an injector. When No. 1 was fired briskly, the injector had to be used to keep water over the crown sheet of No. 1, while No. 2 was too full. The only remedy we had for it was to fire No. 2 very hard and ease up a little on No. 1, a course not always convenient, especially when much steam was needed. Reasoning, that though the gage indicated the same pressure in both boilers, that No. 1 had the advantage, from the greater disparity of heating surface as compared to capacity, I put in a pipe from the front end of firebox of No. 2, and connected it at extreme end of No. 1, thus taking the water driven from No. 1 into No. 2 from its hottest point, and leading it back into the, comparatively,cool part of No. 1. The result was all I anticipated, there is now no trouble in keep ing the water at a uniform hight in both boilers, making steam somewhat easier, probably on account of more uniformity in the quantity of water, and possibly on account of a current in and through both boilers. S. Huntsville, Ala. How to Calculate Quantity of Water Consumed by a Boiler. MESSRS. EDITORS :Will you please answer through the columns of your paper for the benefit of your readers engaged or interested in waterworks, the best method of calcu-, lating the quantity of water consumed by a boiler (in all its parts) through the number of square feet of boiler and flues exposed to fire per hour or day. A. B. C. St. Louis, Mo. [One half square foot of grate surface is usually estimated as yielding 1-H. P. Of course ihis rule is not absolute, owing to the different varieties of boilers and their varying merits. 12 square feet of heating surface is 1-H. P. Same remark applies to this rule. 1 cubic foot of water is required to generate 1 pound of steam. Asyourobj ct is to ascertain the amount of water used for which payment is to be made, we will add a statement in regard to heating buildings by steam pipes which may be advantageous. We have been to considerable personal trouble to ascertain these facts. In the latitude of New York city, where rooms are heated by Steam in pipes running around their sides, the amount of condensation is '357 (three hundred and fifty-seven one-thousandths) lbs. of water per hour for each square foot of superficial surface exposed. Where the steam passes through a coil (inclosBd usually in an ornamental screen) the amount of condensation is '29 (twenty-nine one-hundredths) of a pound of water per hour. This when the temperature is kept as near 60 deg. as possible. A higher degree greater condensation, and consequent use of water. These estimates are merely averagss, as much depends upon exposure of pipes by frequent opening of doors, windows, etc —EDS. The Bedfordian System of Astronomy—The Explosive Theory of the Origin of the Celestial Bodies. MESSRS. EDITORS :There is one great glory in your social compact. Here in England they inquire the length of a man's purse ; you the weight of his brain. Here, however grand the invention or great the discovery, unless the discoverer or the inventor can show that he has " blue blood " in his veins, he is sure to be snubbed more or less ; and the old story, " Can any good thing come out of Nazareth," is uppermost upon their lips, as well in the scientific as in the religious world. These remarks are occasioned by the publication, in one of our magazines, The Studentfii a paper entitled " a New Theory of the Universe," by Mr. Proctor, B.A., F.R.A.S. The fact to which I desire to call your attention is, that this " new theory," as it is called, is a flagrant plagiarism of " New Theories of the Universe," by James Bedford, Ph.D., published in pamphlet form, and entered at Stationers' Hall here in October, 1854—nearly fifteen years ago ! By reference to your file about 15 months since (I have not a copy at hand at the moment) you will see that you have done Dr. Bedford the honor, as well as the justice, to refer to his theories in an article headed, I think, " Relation between Meteors and Comets," and which article I subsequently found quoted in many of the leading j ournals on this side the Atlantic. A comparison of the " Bedford Theories of the Universe " with the theory published in the Student (February, March, and April numbers) and purporting to be Proctor's, will enable your readers to judge to whom the honor belongs of having propounded what is now believed to be the true theory of the Universe. Had Mr. Proctor quoted Dr. Bedford, it would have been seen that his paper was an able and full amplification and verification of that gentleman's theories. This would have done Mr. Proctor credit, and Dr. Bedford but simple justice. London, April, 1869. LIBRA. Phosphorescence of Sugar. MESSRS. EDITORS :I have to record what to me is a hitherto unobserved fact. Late in the evening, a short time ago, I had occasion to step to the cupboard for a lump of sugar. The bowl being empty I went into the nexf room, in the dark, to the store box, and in breaking off the required piece from the proj ecting points, I was astonished to see a flash of light start out from the fracture. I first thought it a light from the lamp shining through the opened door, and through some interstice of my clothing. I shut the door and returned it to the box, and found the flash strangely repeated at every fracturing touch I gave the mass. The sugar was a white coffee quality, damp when bought, but had dried hard. The next day I went to the box, hooding out the light by covering my head and top of the box, but could get no manifestation. The next evening, at the hour of candle-lighting, I repeated the fracturing and found the glowing flash, ample as at first. I should think it the crystallic " od" light Reichenbach announced some years since, but that it seems to exhibit to all alike of the number I have yet led to it. Can you, or any of your readers, inform me respecting its nature and cause ? Leavenworth, Kansas. ? A. C. N. [We can answer our correspondent, first, that the phosphorescence of lumps of dry sugar, when rubbed in the dark, has long been known. The phenomenon may be, however, new to many of our readers, and second, that the odic force of Von Reichenbach is in our opinion a myth. If not a myth it seems odd that other physicists should not have been able to detect it and have corroborated the researches of that celebrated philosopher.—EDS. Capacity of Boilers. MESSRS. EDITORS :I have a tubular boiler, 8 feet long, 17 2-th-inch flues; boiler 2 feet diameter. Engine, 7-inch bore, 10-inch stroke, in good order, new, and works finely. Driving-wheel 4 feet, runs 150 revolutions per minute, estimated 8-H. P. It drives a 26-inch " Queen of the South" corn-mill pulley on mill spindle 12-inch. I work 80 lbs. steam per steam gage, but can only run my engine 20 to 30 minutes when the steam is at 40 or below. I can get up 80 lbs. steam when the furnace is cold in 50 minutes. I pass my feed water through a heater and convey exhaust steam into smoke pipe 3 feet above the boiler. The smoke pipe is 14-inch diameter and 30 feet long. The draft in the furnace is good, especially when the engine is at work. The toiler is entirely covered with masonry. If I have stated the case so that you can understand it, please tell me the trouble, and how I can remedy it. W. C. B. Louisville, Ala. [The boiler referred to has about 80 square feet heating surface. Its diameter is too small, and the number of tubes not sufficient to give a good draft. If the engine takes steam the full length of the stroke, it would require a boiler of double the capacity, but if it cuts off at one-third or less, the same boiler should be sufficient.—EDS. Law of Motion. MESSRS. EDITORS :During the,last year I have been met so often with the assertion of an " absolute law of motion," be fore which everything that conflicts with it must give way, that I have been led to give the subj ect much thought, and have come to the conclusion that the following propositions are true, and would be glad to have them laid before your scientific and mechanical readers that they may state wherein they are not true. 1st. That motion is always a resultant or effect, and never a cause (excepting secondary). 2d. That a resultant or effect can have no law of its own. 3d. That what are called the laws of motion, are, in all cases, the law of the agent used in producing the motion. 4th. That the only absolute law there can be in regard to motion is " that where you increase motion you decrease power," and this can only be maintained for the simple reason that to assert to the contrary, would be to assert that you can produce an effect without a cause. 5th. That there is no law of motion. QUERY.—Assuming a law of motion, as asserted, then if it could be caught and caged would it not be perpetual motion, or at least obviate all the objections to perpetual motion. L. S. P. Ice-making Machinery Wanted. MESSRS. EDITORS :The Frost King slighted us in this latitude last winter, so we are without ice and too far in the interior to get it elsewhere. Will you not favor us with an article in your paper on the subject of artificial ice, indicating what are the best processes and" apparatus for making it cheaply and effectively, with the cost of the outfit for making any given quantity, and cost per tun or pound of making it. If you would call upon parties having processes or machinery for making ice effectively and economically, to advertise in your paper, it might result in their interest and the public good. If indeed there are any really practical and valuable methods of making ice artificially. ICE. Virginia. Singular Effect of Transmitted Light. MESSRS. EDITORS.—The object of this communication is to call your attention to a phenomenon which I have observed for the last year, an account of which will perhaps be of interest to your numerous readers. I have in my dfug store a bottle of pulverized curcuma (turmeric). On the bottle is painted a green ground in the shape of a shield, upon which the name of the contents is painted with black paint. A coating of curcuma adheres to the bottle about l-16th of an inch in thickness, excepting under where it is painted. Under the green ground, being what painters call transparent, a very thin coat adheres, and under the black letters not a particle is found. If a cast was taken inside the bottle a proper fac simile of the shield and lettering would be produced in relief. J. M. SlTTTON. Jacksonville, Oregon. Sleepy-Hollow Chair. MESSRS. EDITORS :I own a cheap but comfortable " Sleepy-Hollow chair," made of pine wood ; it is on rollers, which are screwed to the legs ; these rollers bothered me a good deal by coming off on account of the softness of the wood. It suggested itself to me, that if the screws were dipped in melted glue it would be an improvement. I did so, and now the rollers are as firm as if the wood to which they are attached had been of the hardest kind. This was at least six months ago. I think the experiment a good one. H. J. Washington, D. C. Hot-Air Furnaces as Remedial Agents. MESSRS. EDITORS :Had I supposed my opponent would be catching at straws I would have said that my wife was always a feeble wo-n an, and that probably her life has been saved by the beneficial effects of a hot-air furnace. G. W. H. Weed Cutter Wanted. MESSRS. EDITORS :Could not some of your inventors make a machine for cutting the weeds off ditch banks. Here we have ditches every half acre one way and every five the other, and often times diagonal ones. In old times these ditches were cut by hand four or five times a year; now, for the want of labor, they are either never cut or only once a year, with manifest injury to the crops. A mower in the shape of a traverse plow, with a knifo eighteen laches or t wo feet long, would be the thing. If there is an instrument in existence for executing such work while the crops are growing, let the maker advertise it. S. R. STEWAET. New River, La. THE survey of League Island, which lias been recently ordered by the Secretary of the Navy, will soon be made. A similar survey will be made of New London, Conn. It will consist of soundings as to the depth of water, and capacity of the places for the construction of navy yards. 360 Manufacture of Hominy. Those of our readers who reside in portions of the country where wheat is the staple, will hardly realize the extent to which Indian corn, prepared as hominy, enters into the food of the inhabitants of large sections of the United States. Not only is it a staple article of diet through most of the Southern States, but it also is in demand, to a less extent, throughout other portions of the country, and considerable quantities are also exported. We herewith give an engraving and description of a new and improved hominy and pearling mill, invented by E. A. Duer, of Decatur, 111., which is apparently a very efficient device for the preparation of this important article, as well as the pearling of barley, rice, and other grains. In the engraving, A represents the hopper, provided with the ordinary shoe, B, which is vibrated by the oscillating bar, C, which is actuated by the knocker, D, attached to the main shaft of the mill. The grain passes from the shoe into a vertical trough, E, provided at the bottom with a spiral conveyer, attached to the main shaft, which carries it at a uniform rate into the hollow cylinder, F. This cylinder is divided longitudinally and horizontally, so that the upper half, with the hopper supports, etc., may be lifted off as occasion may require. Within it, revolves the main shaft, Gr, to which are attached knives or beaters, arranged in spiral rows, so as to carry the grain along the cylinder to the end remote from the hopper, at the same time that it is beaten thoroughly by the knives. The cylinder is further provided with a longitudinal recess, H, placed at the top, into which the grain is thrown by the centrifugal force of the revolving shaft and beaters, and the object of which is to arrest the motion of the grain, and bring it repeatedly into violent contact with the knives. The cylinder is further furnished with a diaphragm, I, provided with an opening to allow the grain to pass after being sufficiently beaten. The obj ect of the diaphragm is to prevent the too rapid transit of the grain to subsequent parts of the machine. After the grain has passed the diaphragm it falls through a passage, provided with a slotted gate, which serves to regulate its fall toward the curved chute, J. In making this passage it traverses the lower part of an inclined air chamber, K, and is crossed by a current of air generated by revolving fans in the cylinder,!.. These fans are attached to a shaft in the same manner as those in an ordinary fanning mill, and receive motion by means of a belt from a pulley on the main shaft. The beaten grain is thus winnowed on its way to the revolving screen, M, which is also driven by a belt from the main shaft running on the pulley, N. The air chamber, K, is provided on the back with a sliding door which serves to regulate the blast and affords exit for the dust and detritus. The elements of this mill are all well-known devices, and can be relied upon to perform their special parts of the work in the manner described. It is said to require only about one-half the power required by other mills, to perform a given amount of work. The arrangements for securing a uniform feed and discharge are praiseworthy features. The hull and chaff are completely separated from the hominy, or other grain, by the action of the parts above described. The machine is quite compact, occupying only about four feet square of floor surface. The knives are made of the best cast steel, and require sharpening only about once in four or five weeks, when the mill is doing full work. The machine has been in practical operation for some time, and the quality of its product is said to be very superior. The inventor is confident that the regular feed and discharge secured by the arrangements we have described, will secure general favor for this mill. Offers for territory and propositions to manufacture will be considered. The mill was patented, August 4, 1868, through the Scientific American Agency. For further particulars, address Greo. W. Patterson, owner of the patent, P.O. Box 957, Decatur, 111. Requisites for Good Furnace Grate Bars. The chief results to be secured in a good grate bar are economy in the use of fuel and durability. A great many patterns for grate bars have failed to secure these results, for want of recognition of the principles upon which they should be constructed in order to insure success. Grates burn out rapidly when too large a portion of their surface is exposed to the direct action of the fire, and too little surface is exposed to the air ; and if to secure a large exposure to the cool air they are so made as to obstruct the draft, they fail to give perfect combustion. With such defective grates large quantities of unconsumed gases pass off with the smoke, the effect being to make the furnace, in which such bars are placed, approximate in its action to a gas retort; distillation taking the place of combustion. All other things being equal, that grate will be the best which opposes the least obstruction to draft, presents the smallest surface to the direct action of the burning fuel, has the largest area in contact with the cold air which enters the furnace, and, at the same time, will withstand the effects of expansion and contraction. The form of grate bar shown in the engravings seems to cover the entire ground,all of the above principles being taken into full account in its construction. Fig. 1 is a top view, and Fig. 2, a view of the under side, inclined, to show to advantage an important feature of the bar; namely, the great depth of the central portion which projects below the other parts and forms a wide rib. This feature of course gives great strength, but it performs a still more important office, that of keeping the temperature of the bar at a much lower point, than could be the case without it. The heat from the upper portions is rapidly conducted away by this rib, which is constantly cooled by the influx of cold air from without. Thus is secured one of the main points. A glance at the plan will show at once that the amount of space for the passage of air through this bar, is unusually large as compared with many other styles of bars ; while the portion exposed to the direct action of heat is unusually small. The metal from which these bars are cast is a combination of different irons, which has been found to best withstand the effects of expansion and contraction. Few claimants to public favor can show a better record than this has accumulated during a test of ten years' use in steamers, stationary engines, locomotives, heating furnaces, etc. The bar has been tried in all places and under all circumstances of severity, and found equal to the test. It is in use in more than 5,000 places, including many of the largest steam- I ships, and many of the most prominent manufacturing establishments in the United States, and its merits are attested by a large number of manufacturers and engineers of high repute. It received the highest premium at the fifth exhibition I of the Worcester Co. Mechanics' Association, in Massachusetts, and honorable mention at the Paris Exposition. We commend this grate bar to the attention of all parties interested. Address all communications to Mr. L. B. Tupper, 120 West St., New York. A LOTTERY has just been drawn in Vermont, and among the prizes were 8,000 gilt rings, worth half a cent each, and 150 empty flour barrels, while one young man, who held $300 in tickets, drew a blue-edged plate. This is a fair sample of the various lottery schemes that are so frequently palmed off upon the people. They are complete shaves* Babbitt's Attrition Metal—Directions for Preparing and Fitting. Melt 4 lbs. of copper, add, by degrees, 12 lbs. best quality Banca tin, 8 lbs. regulus of antimony, and 12 lbs. more of tin while the composition is in a melted state. After the copper is melted, and 4 or 5 lbs. of tin have been added, the heat should be reduced to a dull red, to prevent oxidation ; then add the remainder of the metal as above. In melting the composition, it is better to keep a small quantity of powdered charcoal on the surface of the metal. The above composition is called " hardening." For lining the boxes, take 1 lb. of this hardening and melt it with 2 lbs. of Banca tin,which produces the lining metal "for use. Thus the proportions for lining metal are, 4 lbs. of copper, 8 lbs. of regulus of antimony, and 96 lbs. of Banca tin. The article to be lined, having been cast with a recess for the lining, is to be nicely fitted to a former,which is made of the same shape as the bearing. Drill a hole in the article for the reception of the metal, say a half or three quarters of an inch, according to the size of it. Coat over the part not to be tinned with a clay wash,wet the part to be tinned with alcohol, and sprinkle on it powdered sal-ammoniac; heat it till a fume arise from the sal-ammoniac, and then immerse it in melted Banca tin, taking care not to heat it so that it will oxidize. After the article is tinned, should it have a dark color, sprinkle a little sal-ammoniac on it, which will make it of a bright silver color. Cool it gradually in water, then take the former, to which the article has been fitted, and coat it over with a thin clay wash, and warm it so that it will be perfectly dry ; heat the article until the tin begins to melt, lay it on the former and pour in the metal, which should not be so hot as to oxidize, through the drilled hole, giving" it a head, so that as it shrinks it will fill up. After it has sufficiently cooled remove the former. A shorter method may be adopted when the work is light enough to handle quick ly ; namely, when the article is prepared for tinning, it may be immersed in the lining metal instead of the tin, brushed lightly in order to remove the sal ammoniac from the surface, placed immediately on the former and lined at the same heating.—The Practical Metal-Worker's Assistant. A Drunkard's Cure. " Some months %gs a gentleman advertised that he Jhad discovered a sure specific for the cuie of drunkenness. He would not divulge the secret of what compounds he used, but furnished the medicine at so much per bottle. He did not have so many applicants for cure as he expected, considering the extent of the disease. In fact, the more malignant cases did not seen? anxious for relief. They rather appeared to enjoy their malady. A few, however, placed themselves under treatment, and some were cured—whether by taking the medicine or by not taking strong drinks, we are not prepared to say. One of the cured ones had faith in the medicine, rigidly carried out the directions of the doctor, and now has not the least taste for intoxicating drinks ; whereas, one year ago, he was an inebriate, and could not get along with less than a pint to a quart of whiskey per day. " He said that he had, at some trouble and expense, procured the recipe for the preparation of the medicine, which he had published for the benefit of suffering humanity. It is as follows : Sulphate of iron, five grains ; peppermint-water, eleven drachms; spirit of nutmeg, one drachm; twice a day. This preparation acts as a tonic and a stimulant, and so partially supplies the place of the accustomed liqtlor, and prevents that absolute physical and moral prostration that follows a sudden breaking off from the use of stimulating drinks. It is to be taken in quantities equal to an ordinary dram, and as often as the desire for a dram returns. Any druggist can prepare the prescription." We cut the above from an exchange. The prescription named is, as stated, a tonic and a stimulant; but we consider the dose too large by one-third. Considerable irritation of the stomach might be experienced by some patients from so large an amount of the sulphate. The sulphate should also be of the crystallized form. Apothecaries will understand this, but some people might be tempted to prepare the medicine themselves, and obtain for the purpose the dried salt, which is much stronger. We do not believe it can destroy the appetite for liquor, but it may lessen the cravings for it until the habit of drinking has been broken. AN experimental test was recently made at the new public library in Cincinnati, of May's system of making buildings fire-proof. An oven had been built up next to the plastering and joist, which had previously been prepared with metallic lath and concrete, and was subjected to an intense heat for eight hours, but without any observable effect. The architect, builder, and some gentlemen of the Board were present, and seemed highly pleased and satisfied with the result.