The Permeagraph

Nathan C. Johnson
1912 Scientific American  
Scientific AFTER four years of exhaustive experiments the Board of Army Officers appointed to study foot troubles of United States soldiers with a view to offering a remedy has completed its work and has recommended the adop tion of a new kind of footwear-a perfect fitting shoe. Under the old regulations shoes of two patterns were ordered, one a straight and the other a slightly curved last, neither of which, however, gave satisfaction on long marches, and for years the percentage of imperfect
more » ... ntage of imperfect feet in the army has been appalling. On long marches men have been forced to drop out of line on account of blisters, bruises and other shoe troubles. The new shoe, which the board has been so long in perfecting, has a low flat heel, a broad round toe and a quarter of an inch more swing or curve than the old style, the straight last having been abandoned altogether. The investigations carried on by the board were of the most complete and painstaking character, and X-ray photographs resulted in some very interesting informa tion as to the effect on the feet of standing in certain posi tions, and marching in both heavy and light equipment. Civilians might studv these tests in shoe fitting with bene-ficial results, especially those troubled with aching feet. The heaviest tests were made with the soldier in his full uniform and carrying the maximum amount of equip ment of 40 pounds. In the course of these investiga tions the tendency of the feet to spread as the weight was thrown on them, was fully studied, and the X-ray shows the position taken by the various bones of the feet as affected by the changing position and weight. Photographs showing some remarkable experiments have been taken of the feet in the old-style shoe with 40 pounds of pressure on the soldier's back, and the same foot in the new shoe. Invariably in the old shoe some of the toes were pushed completely out of their proper position, but in the new shoe each toe has plenty of room, thus making marching with full equipment as easy as possible. The board dUlling its labors examined thousands of soldiers' feet under varying conditions, carefully taking note and making report on each foot where trouble was caused by a shoe. These feet were also measured and photographed in every conceivable position, ranging from the most complete repose to the severest possible strain under the �conditions of service. The Permeagraph In the final tests at Fort Leavenworth the new shoe proved beyond doubt the success of the board's arduous work. A march of nine days, covering 118 miles, was made by 375 men. Part wore the old-style shoe amI the others the new shoe. The latter finished the tramp easily, while a great percentage of those equipped with the old-style footwear were forced to quit on account of shoe trouble. The method now adopted by the army for "breaking in" new shoes and making them conform to all the little quirks of individual feet, resulting in a perfect fit, is unique. After the shoes are fitted to the soldiers' feet they are made to stand in water to their shoe tops until the leather is thoroughly soaked, then they are marched around until the shoes have dried on their feet, when for ever after the new footwear is as comfortable as the proverbial "old shoe." This may seem a somewhat heroic method, but in practice it is found thoroughly effective. The new· shoes will be made both in black and tan, the former to be used with the blue uniform and with full dress and the latter about the garrison and in the field. THE determination of the magnetic properties of iron by any of the ordinary ballistic or magnetometric meth ods commonly in use is at best a tedious and cumber some process. Without regard to the process employed, it may be fairly said that the nature of the operation and the apparatus is such that only in the hands of a skilled operative and at the expenditure of much time and pati ence can good results be obtained. Further, for a com prehensive view of the results obtained, the instrument readings have to be laboriously plotted on cross-section paper, with often the added inconvenience of deriving these plotted points from the instrument readings. With a view to overcoming these difficulties and at the same time of obtaining permanent, comprehensive rec ords that could be readily filed away, the machine pre: sented herewith, which the writer ventures to call the "Permeagraph," has been divised. It presents several features not contained in any other apparatus and it is believed that it will find a considerable field of useful ness. In much commercial testing of iron, comparative results graphically presented would be sufficient for every ordinary purpose where the iron under test is com pared to a sample of known properties. Such compara tive curves for different irons are shown in the attached print, Fig. 1 . These curves were traced by the ma chine and have not been corrected in any way. The properties of the irons is evident at a glance; and with proper calibration, the exact qualities of each could be scaled off without trouble. The curves shown in Fig. 1 were taken with carefully prepared samples, that is, the length and cross section of each is the same and one end of each has been accur ately surfaced off. This, however, is not always neces sary. The curves shown in Fig. 2 have been obtained with a sample of transformer iron which has simply been cut from the sheet with snip shears and placed on the top of the standard sample in the machine. The curve of the standard sample is the lower one. The curve of the transformer iron is the upper and the properties Of the © 1912 SCIENTIFIC AMERICAN, INC. latter can, if needed, be readily deduced therefrom. These matters will be better understood by reference to the construction of the machine, as shown in the prints. By reference to the photograph and diagram, it will be seen that in general the device consists of a means for measuring the induction of the sam):>le by means of its attractive power on a movable yoke, which is part of a closed magnetic system; and of a drum (15) carrying a piece of paper for the record, actuated by a D' Arson val system (16) in shunt with the magnetizing coil (2). More particularly, the magnetic circuit consists of a massive frame (3) and a movable yoke (4) whose mag netic reluctance as compared to the flux to be induced in the sample (1) when excited by the coil (2) is made very small. The yoke (4) rests on two needle points at (7) on the lower part of the yoke; and is counter-balanced by the adjustable weight (5). The yoke (4), also has an extension, preferably of non-magnetic metal, on its for ward end, carrying the cone-ended adjusting screw (20). From this screw a double-pointed steel pencil (10) ex-
doi:10.1038/scientificamerican08171912-108bsupp fatcat:zwnry45kkvddbbhcjlf2ynz5pq