Phosphatic Bread. MESSRS. EDITORS:—In your issue of August 21, page 119, your correspondent, B. H. J., is perplexed with the disagreement of the "doctors" respecting Horsford's phosphatic bread. As regards the simple disagreement it need not surprise us, for as long as people have different modes of thought we shall always find them giving us diversified and conflicting theories in relation to matters which are but imperfectly understood. The subject of Prof. Horstord's bread is one of very general interest, involving, as it does, the health and happiness of all who use it, and is well worthy of scientific and physiological examination. The writer does not grasp his pen with the idea of deciding the controversy between the doctors, but he may be allowed to, add the other line of tho couplet— When dootors disagree. Disciples then are free. And each person must decide for himself according to the teachings of common sense. There is one point in connection with bread making on which the doctors do agree—namely, that wheat flour in its natural state, unbolted, contains all the elements of nutrition, and when made into bread is a perfect food. But some people think that bread must be white, therefore they take out the most important parts—the nitrates and phosphates, or muscle-making and brain-feeding elements. The object to be gained by the usS of Proi. Horsford's preparation is to restore to the flour the phosphatic elements sifted out with the bran and still leave the bread white. Now the question is, Can this chemical preparation be perfectly similar to the phosphatic elements as they exist in the grain in its natural state ? We believe the doctrine of Dr. Bellows, who maintains that they a're not assimilated by the living organs or appro-piiited as food, but are rejected as poison. We must consider that the laws relating to lite are but very imperfectly understood; also, that chemical law and vital law do not always sustain such mutual relation to each other as we might suppose. No one believes that nitric acid is a healthy article of food or that it might be used as a substitute for beefsteak, yet it is known that nitrogen is the basis of both. In the beefsteak it is organized, while in the nitric acid it is not, and this makes the difference between healthy food and actual poison. If it were possible for us to chemically manipulate soils and fertilizers in such a manner as to obtain nutritious extracts suited to stomachs and capable of building up the organs of human beings we never need be in dread of famine. It may be set down as a principle of animal life that it can never assimilate or vitalize inorganic matter. If we must use white bread let us use it without drugs and supply lost elements by using along with it other articles of food containing them in sufficient quantity to compensate for the loss. J. R. PARKS. Muscatine, Iowa. Where does our correspondent get his authority for the statement that inorganic matter cannot in any instance be assimilated by the animal organism 1 How about the salt used in food 1 How about the iron administered in medical practice to those whose blood is deficient in iron, the result of which is directly apparent in the hightened color of the lips and cheeks, and also in the examination of the blood itself 1 It does not answer to propound general laws that conflict with such ordinary facts as these.—EDS. Nicotine In Lockjaw. MESSRS. EDITORS :—In answer to the correspondence in the current volume of the SCIENTIFIC AMERICAN, NO. 9, page 134, it may be allowable to state that the treatment of lockjaw, or tetanus, by tobacco is by no moans new. Dr. Wood, in his " Practice of Medicine," vol. II, page 833, says: " Many cures, said to have been effected by this powerful sedative (tobacco), are on record ; and it is perhaps among the most efiicacious remedies in tetanus." There are two forms of this disease ; idiopathic tetanus, or that which arises spontaneously in the system, and traumatic tetanus, or that which results from wound or injury, 1x)th equally characterized by a progressive and permanent rigid contraction as well of the muscles of the legs and trunk as of the jaw. The former may arise from the action of cold Upon the body, and is generally curable; the latter is exceedingly fatal. Tobacco, or its extract, nicotine, has also been lised in poisoning by strychnia, the effects of which in poisonous doses may be considered as a variety of tetanus. In 1856, Prof. Haughton laid before the Royal Irish Academy the results of experiments tending to show that the physiological action of nicotine and Strychnia were counteractive of each other; and in 185$, Dr. O'Reilly, of St. Louis, Mo., related the successful treatment of strychnia poisoning by the administration of an infusion Of the dry leaves of tobacco. In tho Medical Times And Gazette for October 2), 1862, will bo found an account of two caSea published by Prof. Haughton himself, In (fas, a oaao of tetanus, caused by a *svre burn, " the man W*B evidently dyig vteu the afcc tine was given. It produced an immediate relaxation of the tetanic spasm of the muscles of expression, of respiration, and deglutition, relief from an agonizing pain, and a lowering of the pulse from 130 to 88 per minute. The nicotine was given in one-drop doses." The other case " was one of idiopathic, subacute tetanus, produced by exposure to cold. In this instance the patient recovered, after having taken, during eleven days, 44 drops, or 26'4 grains of nicotine." In regard to the application of tobacco in strychnia poisoning, may be cited the case of a boy who had taken an estimated quantity of 4 grains of strychnia, as described by Dr. Smyly. " When I arrived he was lying on his back, his head thrown back, chest raised and fixed, limbs rigid, hands clinched, eyelids spasmodically closed. * * * I had an in-f u?ion of tobacco made by pouring a pint of boiling water on about an ounce of cut Cavendish. * * * Cold water was added until the liquid was tepid. I made him drink two thirds of this. Violent vomiting followed. He lay quietly on his back for about five minutes, when he was stized with a violent spasm. * * * I gave him another pint of the infusion in three doses, all followed immediately by vomiting. Another pint was prepared from the same ounce of tobacco ; about a teacupful of this was retained in the stomach for about five minutes; a second was retained somewhat longer. Profuse sweating now commenced, and he slept for a short time. I left him for about half an hour. On my return I found him lying quietly on his back, all his muscles, except those of his legs, relaxed; breathing less rapid ; pulse slower, etc. I turned him on his side, which he was afraid to da himself. He drew up his knees, put his hands under his head, and went to sleep." The boy made a rapid recovery. G. W. Baltimore, Md. Broom Corn In tlic Soutli. MESSRS. EDITORS :—Broom corn has become a crop in the South. The great trouble is to get machinery to clean the seed from the brush after it has been cut. I will be obliged if any of your correspondents will write me giving information where lean purchase such a machine. Broom corn is now worth three hundred dollars per tun, and an acre of ground will produce from half a tun to a tun —the former is a fair average. A hand with a plow and team of mules or horses can cultivate forty acres, though more help will be required to cut, haul, save, and prepare for market. Cannot some of your contributors to the SCIENTIFIC AMERICAN give an essay on the manner of cultivation—'Whether to drill or step drop—the number of stocks to be left; in fine, all the necessary information, irom the planting till the crop is ready for market 1 It will be of great value and assistance to the farmers of this country, where, till recently, the cultivation of cotton was all that was thought of or cared for. BENJ. ROACH. Natchez, Miss. Small Steam Power Wanted. MESSRS. EDITORS :—I was delighted to observe in No. 4, current volume of your journal, a partial description, by Mr. Charles Boynton, of a small steam engine for household use. The great need of such a power is sufficiently manifest, and the mechanic who will furnish a good one may be assured of substantial reward. It appears to me that, to attain success, three conditions are of indispensable necessity: First, absolute safety; second, simplicity of construction and management; and third, the utmost lightness consistent with the required power. Absence of noise in running would also be a valuable quality. I cannot agree with your correspondent that a half-horse power engine " will fill the bill." Less power would suffice for some; others will require that of at least two horses. In the smaller sizes a furnace may be dispensed with, and its office fulfilled by a set of lamps. Boilers of steel would be preferable to those of iron. Compared to these advantages, price would be a matter of secondary consideration; yet a low scale of prices would ensure large sales. The uses to which a low power could be applied with advantage are almost innumerable; but if we consider only the running of the washing and sewing machines—the latter of which are now rapidly killing the women of our land —the demand for it should be enormous. Many will await with impatience the announcement that such an engine is in the market; and, when the SCIENTIFIC AMERICAN shall have passed favorable judgment, its success will be certain. Troy, N. Y. P. J. MCCORT. An Old Portable Railway. MESSRS EDITORS :—In your issue of July 31, is a notice and a view of " Petelers' Portable Railroad." About 1827, I was then about fifteen years old and resided at the foot of Morris street, then called Beaver lane. West street was not complete and did not extend below Cedar street. The Battery had just then been enlarged from about Greenwich street. At the foot of Beaver lane there had been about two acres reclaimed, upon which was a cual yard; Lehigh coal was just then coming into domestic use, and this yard received large quantities of coal, brought there by schooners from the Schuylkill, which was placed in piles or heaps ten or twelve feet high. In order to get it in the remote parts of the yard wheelbarrows were used at first, but that was slow work. There was at that time in the employ of the coal company a young man whose name I have forgotten, who got Up a system of railways somewhat similar to " Petelers'." The Coal was hoisted from the vessels by a crane in tubs holding six. bushols tiach, which tubs were 86t upon a small rail cat, Swinging ujjon round tiara and eoeil dumped. The ears taM upon seetioBs aimt tweWs tfsst is Isngtfej ifiade d stout scantling with three cross-ties mortised in them, one at each end and one in the center ; upon the sections stout strap iron was fastened ; the ends of the sections were fastened together by an iron clasp hooking over staples and keyed; the railways were then ready for use. The railway was placed at any hight desired by placing beneath it frames or horses made for the purpose, and the cars with their loads ran to any part of the yard desired. The whole arrangement was taken up and laid down or altered easily and with very little labor. It must be remembered the use of railroads was but imperfectly known in the United States at that time, and all these things made a lasting impression on my young mind. This system is a very good one for all local uses. Chattanooga, Tenn. E. NEWBY. Crumbling of Pistons. MESSRS. EDITORS :—Several instances of the deterioration of the material in steam cylinders mentioned by your correspondent, George S. Pierce, in your issue of the 28th Aug., have fallen under my observation. In one of these a cylinder bottom was burst out, and the fragments were found so friable as easily to be crumbled between the fingers. The explanation you give is undoubtedly the true one, and the reason such accidents do not oftener occur is because engines are not usually worked with so high a temperature of steam as to produce the result. The case mentioned occurred in an inclined engine on board a small steamer called the Sue Eaves, a tobacco boat on the Green River, Kentucky. The cylinder being too small for the power required, it was necessary to carry very high steam. So far as my observation extends, such accidents occur only where high steam is used, or where the steam is superheated. Where the steam is used expansively there is always more or less water in the cylinder from condensation (except in jacketed cylinders), and tMs water seems to retard, if it does not wholly prevent the deterioration of the iron. Crude oils should never be used in steam cylinders. Pure tallow is a better lubricant, and requires much more heat to decompose it. In cases where it is necessary to use very high steam it were best, perhaps, not to use liquid lubricators at all. Pulverized black lead and soap-stone have been used to advantage, and cannot produce the evil spoken of. Black lead is carbon, but it is not liquid, cannot penetrate, and has no action on the iron. According to the old chemical maxim Corpora non agunt nisi solvta. Dry lubricants should be reduced to exceedingly fine powder and contain no grit. Their use induces considerable wear at first, but the wearing parts soon become covered with a very hard, smooth scale, after which there is no appreciable wear. Newark, N. J. R. D. Improved Wooden Horse Collars Called For. MESSRS. EDITORS :—I occasionally get at the columns of your paper and am always interested in them. Passing a few days here, I read your ntanber for the last of July and Aug. As a planter, I am always pleased with anything pertaining to farm improvements. Of such is Mr. Meyers' horse collar, a picture of which is in the 31st of July No., and it may be a good thing—it looks promising. I want to tell you how we plowed thirty years ago in old North Carolina. We used home-made wooden hames or wooden collars, and they never hurt a mule or horse. If some of your inventing friends would improve a purely wooden collar, it would be a great help to planters. My neighbors, in Texas, have made crops for some years with wooden collars, and no collar can beat them, only they are not handsome, and are a little too heavy. But they need some improvement to be generally used. They could be made very cheap. Will you call the attention of inventors to these views 1 They may be fruitful of some good. THOS. S. WILSON. New Orleans, La. TIe First Circular Saw. MESSRS. EDITORS :—I send you the remains of a round saw which I made in the year 1813 or 1814, when not over 13 years of age. It has been lost many years, but last spring was found while working my garden. I send it to you, not for its intrinsic value, but for its antiquity, claiming that it is the first circular saw ever made or used in America. My father, the year this was m ade, inquired of all the hardware merchants in Albany and Troy for such a saw, but no one there had ever seen or heard of such an article. This was made of sheet iron, attached to a wooden shaft, used for splitting -in. bass-wood boards for old-fashioned wheel rims, made 2000 revolutions per minute, and, we all thought, performed most admirably. My father, immediately copying mine, made one from the wide part of a broken handsaw, which, although almost worn out, is still in good working order. Now, if you think my claim, as the young inventor of the circular saw, is unjust, please correct it from any authentic records in your possession of an earlier date. LEMUEL READ. North Brookfield, N. Y. [Messrs. Hoe & Co., of this city, have been engaged in the manufacture of circular saws for 40 years, but, so far as we are aware, our friend Read is at the top of the heap in antiquity.—EDS. Smooth Cutting Edges for Reaping Machines a Fallacy. MESSRS. EDITORS :—I was very much surprised to notice one of your correspondents, in Nos. 5 and 8, current volume, advocating smooth cutting edges in reaping machines. Now, I have had fifteen years' experience irt using reaping machines, and 1 have never yet seen a dull serrated siskte see* ttoa t**t teams se by cutting p*ta akne. I have a machine, now, that has been in use six years, and has cut from 60 to 80 acres of grain a year, and yet the sickle sections are as sharp as ever, except those that have come in contact with stones and other hard substances. I believe that the smooth edges would cut just as well, so long as they remained sharp, but they would, and do, get dull so easy that the difficulty of keeping them in repair is the reason they are not used for cutting grain. Your correspondent ought to know, that serrated sickle sections are made as hard as it is possible to make steel, and if they come in contact with nothing but straw, they will last a lifetime, whereas the smooth-edged cutters must be made softer, so that they can be ground when they become dull. I think it is unfair to call the makers of reaper knives idiots and lunatics, when, really there is so little fault to be found with them. There is more room for faultfinding in the way the other parts of the machines are made. For instance, the use of cast iron where wrought should be used, and wrought iron where steel should be used. In fact, reapers should be as light as possible, and yet be strong. I have seen reaping machines that looked almost strong enough for a saw mill, and yet come to grief very goon. They were so heavy that their own weight broke them to pieces in drawing them over the ground. H. MARTINSON. Hawksville, Ontario.