Document wd2n6gZK2roa9kwNQw7NEdB

128 The Literary Digest for May 3, 1920 SCIENCE AND INVENTION Continued Twenty Minutes' Use of your range will cook this meal Be suce the fireless cook&tove you buy has the triple seal topshown, withthe famous Water Seal to lock the heat in. FREE BOOK "Delicious Fireless Cooked Dishes" is a fireless cooking demonstration withcolored photo* graphsand recipes. Write for thisbooty address Dept. 26 It takes only twenty minutes to heat the 'Toledo Tireless Cookstove radiators on your kitchen range. Foods are not pre-heated; all the cookingisdone by the imprisoned heat of the fireless cookstove. Meats--even the cheapest cuts-- have a new delicacy and richness, because they are cooked without water,in their own juices. Vegeta bles, cooked with butafewspoon-' fuls ofwater,lose none oftheir fine flavor, are tender and delicious. Breads, biscuits and pies are all evenly and beautifully browned, thoroughly cooked--never overor under-done. Everything has a better flavor, because the good ness is cooked in instead of out. Play more. Get out every afternoon. Your fireless cookstove will cook die evening meal while you are not home. Toledo Fireless Cookstoves retain heat intense enough to do any kind of rapid cooking because of the patented Water Seal, the third and final heat-lock ofthe triple seal-top. In this Water Seal--a groove in the aluminum compartment lining into which the cover fits--water collects and forms a barrier against escape ofheat.The locked-in heat cooks almost as quickly as your range and with infinitely less fuel. Other features" which are found only in these cookstoves are the patented Automatic Pressure Reg ulator, which releases the surplus steam and permits the wonderful browning for which Toledo Cookstoves are noted; the scientifically arranged insulation that prevents heat loss through compartment walls;and the seamless,aluminum compartment lining, five times the usual thickness and durability. The Toledo Cooker Co. TOLEDO - OHIO the factory departments were swept 'up f during working hours the average lost time per operative was five minutes on this. This gave a yearly loss on five hun dred feniale operatives of approximately sixty-six thousand working hours at twenty cents per hour, approximately thirteen thousand dollars,'eliminating the usual lost time before quilting, and ignoring the fact that the'men in the department quit work at the same time tins girls did. "It was not hard to see that providing a separate exit for the women and separate pay - windows on pay-day supplied iho needed segregation at the congested hours. Sweeping at night cut out the disturbing expense incident to doing this in the daytime." , HOW FAINT " DRIES" WHEN a wet towel "dries'1 the j water witli which it is saturated | evaporates. There, is uo water in oil paint, [ nor any other thing that will evaporate, except occasionally when turpentine is used to thin it. The thing that "dries" is the oil; and this it does, not by leaving tho paint but by solidifying by combination with tin* oxygen of the air. This oxidation may take days it tho oil is left alone, but V it may be hastened so as to take place in a few hours by using certain metallic sails.' We are told by V. P. Ingalls, writing in Chemical and Metallurgical Engineering OS 'i till iI|n i 1 ^ solvedlalehigt pv tt Liquids capable \ of oxidation are few and are all oils. Many , oils oxidize, but few solidify in so doing. I Linseed-oil, exprest from flaxseed, is the j must important and is almost universally j Used with paint. Writes Mr. Ingalls: i "When Unseed-oil is exposed to tin* air i it absorbs oxygen, increases in weight and , volume, passes through a stage of highly increased viscosity, and finally l>cemm*s a solid, lough, rubbery mass. The. rapidity of this oxidation, perhaps indeed even its extent, is dependent upon a number of conditions, chief among which are the temperature and extent of surface exist'd, especially the latter. Exposed in layers 0.001 to 0.000 inches in thickness, on glass plates, at a uniform temperature of 75 t\, it requires from about six to fifteen days (according to thickness of layer, quality, and kind of oil j for the film to become `dry to touch.' and in ordinary parlance is then said to be `dry,' altho it is very well and generally known . that the film combines to harden pro- ` gressivcly for a very long and definite time thereafter. Obviously, this reaction is very slow. . "If various pigment colors be ineorpo- ! rated with the oil by a process of median- j ioal grinding, and iho mixture so obtained i be spread out in thin layers as above, wo f observe some very remarkable diff'ei .lives 1 in the drying time. Some pigments, as, for | instance, umber, will shorten it to less | than twenty-four hours, while others will | lengthen it into weeks, as in the ease of | carbon blacks; and certain of the anilin- | / SCIENCE AND INVENTION Coniimted n>lir tancate lakes (made from magenta vr mo'hyl violet) may inhibit the oxida tion of the oil. to such an extent, that even after months of exposure there remains inly a sticky, gummy film in nowise ac ceptable as a good paint coating. "This quickening effect of umber has long been known; just how long is a /tinner of some doubt, but certainly for two or three hundred years, W^^^ad, $mUSs drying process; but., without at tempting, to follow the bisTorical develop ment, we may come down to the early half of the nineteenth century when good `boiled oil' and `oil varnishes' which dry in twenty-four hours or less bad become commercial commodities.................. " Because* the best of these were pre pared by !qil with. ends, notably litharge and rei^leaifiv'and because t he oil was still further oxidized by the air during the beating process, there became prevalent a theory that the normal drying time was shortened by virtue of the fact that t he oil so treated was already well oxidized and only a limited exposure was necessary to complete the process. This theory, oltbo not now tenable, contained an element of truth, in that coatings with such oils gave harder films than most others marie at that time, and was further supported by numerous instances where oil winch had merely been heated rather strongly in the air showed greatly in creased drying power. Without direct knowledge of how this heating was done, nor under what circumstances, we may now assert quite positively that the in creased drying power was duo to some oilier cirehmstance than were heat and the atlendaut air oxidation." It is now known, Mr. Ingalls tells us, that the drying process is. dependent on tho. presence Jn tjbe oil of certain fatty acids, known collectively'-in the^<case,,o| Jinseed-v oil as "imolcic ae d ' It i tiin ,il formed by these pcid^witb certain metaU. notably cobalty. inaaganese,. . and dead, that are the real "dniqrs," or stimulants of oxidation. Be says: ` "Concerning the quantity of those driers required to produce the maximum acceleration, much depends on conditions. Unless the metal is in solution or retained ia what may be termed the active field, it has little or no power. Whether the solu tion is crystalloidal, partly colloidal, or wholly colloidal is open to discussion, but then a precipitate forms it is (at least relatively) inactive, even tho it may retain <H>Dsidcrablc metal. "Roughly speaking, it is easy lo bring <he drying time down to seven or eight tours for linseed-nil, but to go below this time requires extraordinary drier. With lead alone it is difficult to reach this speed rith any amount within reason. With manganese three to five parts in ten .housand will suffice. 0>balt requires about the same, perhaps slightly less............ "In general practise, therefore, it is customary to use lead for character, and jack it up with manganese or cobalt for 'peed, A good strong-drying oil will reoerally show on analysis, in parte per 10,000: lead, 50 to 150, and manganese, HolS." The Literary Digest for May 8. 1920 131 8