86 



POPULAR SCIEI^CE I^EWS. 



[June, 1888. 



cylinder perforated or covered by wire cloth, filled 

 with some absorbent material, as dry ashes, fire- 

 clay, or asbestos. These, when charged with oil, 

 and introduced into the stove, will burn as long as 

 any oil is left in them. They give no smoke if the 

 draught is well regulated, but do waste oil by 

 throwing it off in the form of unburned gas. The 

 air and steam sprays are simply atomizers, the 

 atomized jet being thrown into the stove and ig- 

 nited ; these require either steam or compressed air, 

 the object being to produce a finely divided spray 

 of oil, so completely intermingled with air, that the 

 oil is compelled, as it were, to burn. No oil is 

 wasted in these methods of burning, unless too 

 much oil is thrown in for the air-supply. The fifth 

 method consists in projecting the oil in minute jets 

 against firebricks, which soon get hot enough to 

 partially decompose the oil. There is considerable 

 waste of oil in the form of unburned gas. The last 

 method is by forcing the oil through minute perfo- 

 rations in common gas-pipe, which becomes highly 

 heated, and soon produces more or less gas from its 

 oil. There are many forms of burners, but they 

 all work on the same principle, and all produce 

 considerable unconsumed gas. The reason for this 

 is. that kerosene requires quite a high heat to effect 

 its decomposition into gas, — more than can be ob- 

 tained easily by the heat of its own combustion on 

 coils or pipes. The results of the six trial.s were 

 as follows : — 



G-allons consumed 

 in 10 hours. 



1. Wick burners 2.25 



2. Air spray 2.40 



3. Steam spray 2.55 



4. Projection against firebrick .... 3.50 



5. Perforated pipe and heated coil . . S.fiO 



6. Fuel cartridges 3.80 



The heat was maintained, as nearly as possible, 

 at the same degree in each trial; or, in other words, 

 the results in heat are supposed to be equal. To 

 obtain the same amount of heat by means of coal, 

 required forty pounds in the ten hours. As before 

 stated, the space heated was about eight thousand 

 cubic feet; and there were five large windows and 

 four doors for cold air to enter through numerous 

 cracks and crevices. 



These results, while not exactly conclusive, are 

 exact enough to point strongly to the fact that 

 kerosene oil can never compete with coal in matter 

 of economy for heating houses. The crude petro- 

 leum might do so, if any means could be devised to 

 evercome the exceedingly bad odor of the oil. On 

 the other hand, when short, quickly lighted fires 

 are needed, as in the summer season in all our 

 dwelling-houses, it becomes, if not an economy, at 

 least a great convenience. Strange to say, the old- 

 fashioned but somewhat improved wick burners 

 are still in the front, as being the most economical 

 and easily managed. The spray burners give good 

 results too ; but they produce a disagreeable noise, 

 which alone condemns them for household use. 

 Numerous devices have been put before the public 

 for hurninq water along with kerosene ; it is always 

 safe to condemn any and all of these, since anyone 

 slightly versed in chemistry can demonstrate the 

 fact that it requires as much heat to decompose and 

 burn the water as it gives out in burning, and there 

 is no gain whatever. Another thing: it is useless 

 to expect to obtain more heat from the oil than it 

 contains; yet there are plenty of pretty well edu- 

 cated people who believe that petroleum is the 

 coming fuel, when the right process is found for 

 burning it. In regions where petroleum is cheap, 

 this may become true; but we can hardly expect it 

 in the New-England States. 



The best results obtained thus far for burning 

 crude petroleum under boilers is the consumption of 

 120 gallons of oil to equal one ton of good coal ; but, 



with leakage and waste, it may be put at not far 

 from 130 to 150 gallons on a steady run. In the 

 experiments mentioned, we have seen that it re- 

 quires from 2.25 to 3.8 gallons of refined oil to 

 equal 40 pounds of coal, or an average quantity of 

 125 gallons to equal one ton of coal when used in 

 small stoves ; thus agreeing very closely with the fig- 

 ures obtained in the large way under steam-boilers. 



The stumbling-block is found in the fact that no 

 inventor has yet found out how to thoroughly mix 

 the great quantity of air with the oil which is re- 

 quired to make combustion perfect, '\^■hen this is 

 done, the full benefit of the calorific power of petro- 

 leum can be had. It appears to the writer that in- 

 ventors would do well to drop the " burning water " 

 theory, and devote their time to improving the wick 

 burners or to perfecting some form of apparatus 

 which will introduce an unlimited amount of air 

 with the burning oil. Neither is the system of de- 

 composing the oil and burning its gas feasible on 

 the small scale, in the writer's opinion. 



A rather pretty experiment, and one which illus- 

 trates the necessity of fully and finely dividing the 

 oil, can be shown by any one who possesses one of 

 the common atomizers used for perfume. If this is 

 filled with kerosene oil, and sprayed into the air, 

 observing to spray through the flame of a candle or 

 alcohol lamp, a most beautiful flame is produced, 

 two feet or more in length, which is perfectly free 

 from smoke or odor. One will be surprised at the 

 great size and beauty of the flame produced this 

 way. 



Portland, Me., April 1. 



THE SEPARATION OF TIN FROM 



ANTIMONY. 



The slags, essentially a silicate of iron, contain- 

 ing, besides notable quantities of tungstic oxide, 

 traces of lead, copper, and titanic oxides, are treated 

 by the following method: After careful grinding 

 of two grams of the slag, the portion is at once in- 

 troduced into a platinum dish, and treated with an 

 equal mixture of pure hydrofluoric and hydrochloric 

 acids. The whole portion of the slag, after digest- 

 ing for a few minutes, is entirely decomposed; 

 the greater portion of the SiO^ being volatilized 

 as SiF^, the remainder passing into solution, and 

 containing, besides, the whole of the tin, as SnCl^, 

 besides other impurities. The solution, after being 

 filtered, is gently heated, and saturated with SHj ; 

 the whole of the tin, besides the impurities present, 

 being precipitated as sulphides. The precipitate 

 collected is boiled with NallO, to separate the bis- 

 muth and cupric sulphides pre.sent. The solution 

 now contains pure sodio-sulpho-stannate of anti- 

 mony and tin, which is re-precipitated by the addi- 

 tion of IICI; the antimony and tin sulphides now 

 obtained are decomposed by means of aqua regia, 

 and contain a large excess of IICI, both of which 

 pass into solution as antimonic and stannic chlo- 

 rides. The solution, evaporated to a small bulk, 

 to deprive it of any large excess of HNO3 that may 

 be present, is diluted with a moderately weak solu- 

 tion of HCl; to the acid solution obtained an 

 excess of potassium ferrocyanide is added, and 

 the solution — which should now possess a clear 

 blue color, provided sufiicient K^FeCy^ has been 

 added — is allowed to boil. The whole of the tin is 

 thus precipitated as stannic ferrocyanide, being 

 insoluble in an acid solution ; and, as there is no 

 such compound as antimonic ferrocyanide, the 

 antimony consequently remains in solution (which 

 may afterward be precipitated by SIIj, and esti- 

 mated in the usual manner). The precipitate con- 

 taining the tin is now dried and ignited, a few 

 drops of IINO3 being added, which speedily de- 

 stroys the organic matter present. The residue is 



now introduced into a crucible provided with a 

 tubulated lid, and reduced by means of hydrogen 

 or coal-gas, allowed to cool, and dissolved by means 

 of IICI; the tin precipitated as sulphide, oxidized 

 with UNO 3, and determined by the usual method. 



The analysis and separation of tin from anti- 

 mony in alloys may be conducted by precisely the 

 same method, save that the alloy is dissolved by 

 means of aqua regia in place of HCl + IIF. 



The precipitated antimony sulphide, after the 

 separation of the tin by means K^FeCyg, should 

 possess a bright reddish-orange color, entirely free 

 from any brown coloration. — H. N. Warren, in 

 Chemical News. 



AN APPLICATION OF STATIC ELECTRICITY. 



Mr. WiMSHURST, the inventor of the induction 

 machine, has applied the latter very ingeniously to 

 the illumination of bodies having a rapid motion. 



The following experiment will make the appli- 

 cation under consideration understood. If, at a 

 velocity of several thousand revolutions per min- 

 ute, we revolve a disk upon which there is printing 

 in small characters, and if a series of sparks be 

 passed at the moment that the characters are in a 

 vertical position , the printed portion can be read. 



To succeed in this, it is necessary to have a 

 commutator that makes the sparks start from the 

 machine at the desired moment ; and this would 

 naturally be done by actuating the commutator 

 through the revolving disk. It would be possible 

 in this way to examine a rapidly revolving wheel, 

 and this in certain oases might prove useful. — 

 La Lumiere Electrique. 



INDUSTRIAL MEMORANDA. 



Mustard Oil has recently been recommended 

 as a lubricant. It remains perfectly fluid at a 

 temperature of 14° F., and will keep unchanged 

 for years. 



At Topkka, Kan., several Sprague motors are 

 in use for raising bricks and mortar, etc., upon the 

 scaffolding of a large building in course of erection. 

 The method proves to be much more economical 

 than that of the employment of a steam crane, 

 because the work is essentially of an intermittent 

 description. 



Telegraph poles are preserved in Norway by 

 making an auger hole about two feet from the 

 ground, in which four or five ounces of sulphate of 

 copper in coarse crystals are placed and plugged in. 

 The chemical is gradually absorbed by the wood 

 until its whole outer surface turns of a greenish 

 hue. The sulphate requires an occasional renewal, 

 and is said to be a perfect preservative. 



Dynamite for Building. —Paradoxical as it 

 may seem, the latest thing for which dynamite has 

 been employed is not the blowing-up of buildings, 

 but, on the contrary, the laying of their foundations . 

 This new development is due to M. Bonnetond, a 

 French engineer. When a foundation has to be 

 laid in wet ground, he bores a hole from ten to 

 twelve feet deep and an inch and a half wide. 

 Into this hole he passes a string of dynamite car- 

 tridges, which are then exploded. Not only is a 

 cavity of a yard wide produced by the explosion, 

 but the expansive force of the dynamite drives the 

 water out far beyond the sides of this cavity, and 

 it does not return again for more than half an hour. 

 In the mean time the workmen clear the cavity, 

 and introduce quickly settirtg concrete; so that, 

 when the water returns again, it cannot injure the 

 foundation. The method has been put into prac- 

 tice during the building of an enceinte at Lyons; 

 and a rapid rate of working is said to have been, 

 attained thereby. 



