true in the case of the pieces of spruce, which are to form the sides or uprights. The holes for the rungs should be bored with a 15-16ths inch auger. The rungs A C B S FIG 1. WINDOW FIXTURE FOR VENTILATION WITHOUT DRAUGHT. Sectional view. themselves should be turned from hickory, or, as a substitute, from tough white oak, and the ends brought to shape by means of a hollow 1-inch auger. The various parts are then ready to be joined together. If it is desired to work among dense branches, the pieces of spruce, in drying, may be brought to the shape indicated in the drawing. A hook at top, adds to the safety of the ladder. Ventilating a Bedroom Can you suggest some system of adequately ventilating a bedroom without draught?—T. A. J. The following method is said to have given satisfaction. A regulation storm window sash from which the lower panes have been removed, is put in place. Instead of the panes, some stout cloth is used. It is better, ordinarily, to use some flowered cloth, say silk or cotton, as such material gives a pleasing effect. With the inside window open, no draught will be felt. A more permanent system may be installed as follows: Take an ordinary curtain roll, and remove the little dogs that hold the cloth from unwinding. The curtain itself should be of unsized material. Fasten the roller R to the win dow stool S (Fig. 1). The loose end of the curtain (c) should be secured to the bottom rail of the sash (4). When the window is raised, the curtain unrolls, and the opening in the storm frame is automatically covered. In Fig. 2, D represents a strip which should be nailed in the position indicated, to hold the curtain at the side. A sheet-metal cover B is for the purpose of protecting the roller. If one prefers, the upper instead of the lower half of the window may be fitted in this way. Condensed Steam as Feed Water What danger arises from using the condensed steam from a surface condenser as feed water for the boiler.-A. H. O. When the condensed steam from a surface condenser is used as feed water for the boiler, there is danger from cylinder oil entering the boiler with the condensed steam. Oil separators extract nearly all the oil, but it will accumulate very fast. If oil enters the boiler, the resulting conditions will vary with the nature of the oil. Animal oil is more destructive than mineral. Mineral oil in small quantities under ordinary conditions, does not seem to cause serious effects; when present in large quantities, it accumulates at the lowest point in the boiler, or coats the entire inside. In the case of animal oil, it accumulates in a solid mass at the lowest point of the boiler. This mass is a very poor heat conductor and prevents transmission of heat from the boiler plates or tubes, causing overheating at this point. The section will then yield under the boiler pressure, and cause bagging or possible rupture. Photographing Blue Prints Can blue-prints be photographed success-, fully?-N. H. The following method of photographing blue-prints is said to have produced good results: Bleach the print in dilute aqua ammonia, and then immerse in a weak solution of tannic acid. This latter may be mixed by dissolving a heaping teaspoonful of dry tannic acid powder in a glass of water. The drawing will stand out in nonactinic red; a photograph of same will give a negative having black lines on clear glass. Backed with white. paper, this can be used for copy in the photo-engraving process. Demagnetizing a Watch Will you suggest a way to demagnetize a watch?-H. F. F. The watch should be set securely before one of the poles of an electro-magnet of high power. Before the turning on of the current, which should be done gradually, the watch should be rapidly revolved, though this is not necessary if an alternating current is used. Either a laminated case, or none at all, must be used, in this event. At the end of some 12 or 15 seconds, the watch may be removed. Rack Beneath Table I should like to place beneath a rough working table an adjustable rack that could be easily removed.-T. J. R. The accompanying drawing shows very clearly. a serviceable and cheap method of making such a rack. Saw notches inch deep in the legs of the table, and with the use of wire, the crossbars may be held in place. Loose boards may then be placed across, and quickly removed, if the occasion should require. The rack may be raised or lowered to the height desired, in an instant. Ill-Working Accumulator The accumulator of my electric runabout is unsatisfactory, the service being irregular. Can you suggest the cause of the trouble?-H. A. P. There is probably some obstruction or resistance to the proper flow of current from the positive plate of the cell, through the electrotype, into the negative plate. The grids may not be in contact; connections between the plates may be broken; the electrolyte may be too strong or too weak; a short circuit may have been formed by the active materials dropping out of the grid and accumulating in the bottom of the jar; or a coating of non-conducting material may have formed on the particles of the active material. Making Gravel Roofing How is gravel roofing made?—T. H. J. The surface of the roof is first covered notches &" Seep #14 copper wire. METHOD OF ADJUSTING CROSS-BAR FOR TABLE-RACK. with dry felt paper. Upon this are next laid several layers, from three to five, of tarred felt. The various layers should lap over the seams, so as to make all snug and tight. Where walls and chimneys intervene, the felt should be turned up four or six inches and nailed to the obstruction, strips of wood first being laid over the felt. Cementing Old Shingles Can old shingles be covered with cement. satisfactorily?-L. T. M. It would hardly be worth while to make the experiment, as the results would doubtless be unsatisfactory. The only method, short of concrete shingles themselves, is to cover the roof with expanded metal laths. These should be bent up well at the walls. Over these, lay a covering of concrete, about an inch in thickAt best, however, this would serve but temporarily, and would not be advisable treatment for a roof of any value. ness. 674 House Tank on Roof Please print a drawing showing the proper way to make pipe connections for a house tank. Of what material is it best to construct such a tank?-J. D. G. The accompanying illustration shows the ordinary type of tank that is used in private dwellings. With regard to location, the tank should be at least ten feet above the level of the highest fixture to be supplied. Formerly lead lined. wooden tanks were extensively used and in some places are still. But carbonates or sulphates of lead are liable to be dissolved from the lining, with deleterious results to the human system. Of course, if the tank is merely used to store soft water for bathing purposes, this is immaterial. Iron tanks are perhaps more satisfactory, on the whole. Coal vs. Water Gas Is danger of asphyxiation greater from water gas than from illuminating coal gas?-A. D. E. Chemists agree that inhalation of illuminating coal gas in small quantities is dangerous neither to life nor health, though continued exposure may result in chronic poisoning, owing to the presence of a small percentage of carbon monoxide. Water gas contains a much larger proportion of this carbon monoxide. Hence a state of unconsciousness is very quickly induced by the inhalation of water gas. One per cent of this gas in air is fatal. Process of Electrotyping Please describe the process of electrotyping. -G. P. An important application of electrolysis is in electro-plating a portion of letter press, a form or page, for use in gravings for printing from, instead of newspapers or books, and in copying enusing the original blocks. The set-up type. must be carefully justified and very firmly locked up, to withstand the pressure used in making the wax impression. First the forms are cleaned from printer's ink and dried, then brushed over with plumbago to prevent the wax from sticking. The molding composition, consisting of beeswax with five to twenty per cent turpentine, is poured into the molding case, and must present a smooth even face, free from cracks and bubbles. This surface is carefully and evenly brushed with plumbago and polished and into it the face of the type is forced by a hydraulic or toggle press. The mold is then carefully removed and built up or. corrected by the addition of wax, where necessary. The mold is now plumbagoed and all excess of plumbago removed by a brush or bellows. Copper wire conductors are now embedded in the mold, which is then made the cathode in a saturated solution phuric acid. Large copper anodes keep of copper sulphate acidulated with sulthe liquid stocked with the metal. Copper is deposited evenly on the surface of the mold, to about the thickness of good book paper, or heavier, according to the use to which it will be put. When a sufficiently thick layer has been obtained, the mold is taken from the bath, and the wax removed by pouring hot water over the surface of the copper, which may then be gently stripped off. A solution of caustic potash removes the film of wax from the copper shell, which has now to be backed up with stereotype metal. After washing the cavity of the shell with a solution of zinc chloride, it solder, and then melted stereotype metal is warmed and coated thinly with tinner's eighth of an inch thick. This will withis poured in to make a layer about oneplate is then carefully corrected by a stand the pressure of the printing. The finisher and mounted on a block of wood. Amundsen-Master Mariner By J. Mayne Baltimore APTAIN RAOLD AMAMUNDSEN of Norway has just completed a job, on which the most daring mariners of the world have been working for five centuries. Where Sebastian Cabot, Frobisher, Henry Hudson and Sir John Franklin failed in finding a navigable passage from the Atlantic to the Pacific through the polar seas north of the American continent, the daring Norseman succeeded. He did more than discover the long-sought Northwest Passage. He discovered also the north magnetic pole, that spot where the needle of a compass points to the center of the earth. This also has been an object of search for many years. made the perilous trip. Three years ago, with the blue-barred flag of Norway flying from her masthead, she set out on her perilous voyage, and though worn and weather-beaten, she was still stanch and seaworthy when she quietly dropped anchor in the waters of San Francisco Bay, her voyage over. The men composing the crew are stalwart sons of the North, who showed none of the hardships of three years' wanderings in the icy seas of the arctic circle. Their feat is a marvelous one. Never before has a ship that entered the northern waters of North America found an outlet in the Pacific. The Gjoa is of but 47 tons burden, 73 feet in length, and 20 feet in width of beam. She is essentially a sailing vessel, Almost equally interesting is Captain equipped, however, with gasoline motors. Amundsen's an This auxiliary power availed her but little, for on entering the northern seas she was speedily disabled by the propeller shaft coming in contact with an iceberg. The Gjoa's hull is of cavernous depths. Abaft the wheel and below decks are the officers' quarters, consisting of sleeping rooms, library and dining room. The walls of the captain's cabin arc decorated with pictures of Nansen. who is an intimatc friend of Amundsen. The library consists of scientific works and fiction. The cooking quarters are amidships; .those of the crew are forward. So cramped are the accommodations of the latter that there is barely sufficient space for two men to stand up comfortably, the bunks being set against the very stem of the vessel. The instruments that record the results in the matter of the dis covery of the magnetic pole, and which will prove of tremendous value to science, have been sent to Professor Schmidt of the Potsdam Meteorological Observatory. From this quarter the results of the expedition, which are being eagerly awaited on all sides, will be given to the world. A Producing Artificial Food By Albert Grande SHORT time ago the daily press contained some rather sensational information, according to which Professor Emil Fischer of Berlin, who for his discovery of artificial synthesis of sugar had been awarded the Nobel Prize, had succeeded in preparing from coal a nourishing food called polypeptide. It may be said that this information, though containing some truth, was greatly exaggerated and like so many other sensational news, is apt to mislead the mind of the non-initiated. An explanation of the problem in question and of the results really obtained by Dr. Fischer will therefore be needed. One of the most important and indispensable classes of foods is that of proteids or albuminoids, of which the white of egg is the most typical representative. These substances are tissue formers and are nourishing in so far as they give weight to the body. When split up, a molecule of proteid yields another molecule showing some new properties, and the white of egg has thus to be changed to what is called a "peptone" by the digestive process, in order to pass through the walls of the stomach and intestines. Similarly, wheat, meats, etc., will give a number of different peptones which in turn yield what is called amido-acids. Though the chemistry of amido-acids has been very successful indeed of late years, in ascertaining the structures of some of these bodies and in preparing them artificially, it has not been possible, so far, to prepare by an artificial process the true proteids or albuminoids. Dr. Fischer has, however, just succeeded in converting animo-acids into their anhydrids, which are called by him "polypeptides." The higher terms of this class of bodies are so like natural peptones as to their external properties, their color reactions and behavior in regard to acids, alkalies and ferments, that they may be regarded as their closest relatives, their production constituting a first step towards the synthesis of natural peptones and albuminoids. It will doubtless require the patient work of many years to develop this process to the real production of albuminoids. or nourishing food, but the importance of Dr. Fischer's discovery lies in the fact that the path on which success must be forthcoming has been traced once for all. Whether the food thus artificially produced will be less expensive than natural food cannot as yet be decided; but should this be the case (and there is some probability of its being so) Dr. Fischer's discovery would doubtless rank among the most important ever made, and should prove a boon of tremendous value to humanity. |