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Scientific And Useful

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I Dr. V. II. Wahl tells in the Journal of Iii'lu-try vli:it celluloid is and bow it is made. Briefly defined, celluloid, lie says, is a species of solidified eollodion, produoeii by dissolving gi'D cotton (pyroxylin) in eaniphor with the aid of heat and pressure. The gun cotton is grqund in water to a fine pulp in a machine similar to that used ia grinding paper pulp. The pulp is then subjected to powerful pressure in a pcrf'orated ves8el to extract the bulk ot' the moisture, but slill leaving it slightly moist. tor the next operation. This consists in tlioroughly incorporating tinely comminuted gum camphor with the moist gun-eotton pulp. The proportions employed are said to bc one part by weight of camphor to two parts by weight of the pulp. With this mixture any coloring matters required can now be incorporated. The next step is to subject the mass to powerful pressure in order to cxpel f'rom it the remaioing traces of moisture and incidentally to iflect also the more intímate contact of the oaniphor with the pulp. The dried and compressed mass is next placed in a niold, open at the top, into whieh fits a solid plunger. A heavy hydraulic pressure is brought to bear upon the plungcr, and at the same time the mixture is heatcd by means of a steam jacket surrounding the vessel to a temperature of about 300 Fahr. When the nui-s is taken out of the press it, hardens, and ac quires extraordinary toughness and elas-ticty, which are the distinguL-hing characteristic of this remarkable product. Celluloid is very largely usi d as a sulmtituto br ivory wliich is imitatcd with great succeos. Tor loisè r-liell. malacliite, mothi r ofpcail, coral and other (xihtlj and elegant materials are uso su MK'cechfully imitated that an expert can hardl deiect the original f runi thecopy. Celluloid is also u.scd as a substitute lor linrcelain in llie manufacture of dolle, whicli will stand a good di al ot ruugh usage with out breakioi; Quite recently, too, it ha beencombinud wuh linen, and used for shirt Imimiuis, cull and collars. The great artei-ian well at Buda-Pesth. begun in the year 3868, is duw finuhed DuriDfi the progresa of the wmk many interebting f'acts relaling to geology ami uu dergiound temperature were collei'ttil. Sonie of these are given in the' Km i The total depth ia 3,200 feet, and thu dm pcrature of the water is 165 Fahrenheit. The teniperatureof the mud brought up by the borer was taken every day, and was tbund to increase rapidly, in spite of' tin loss of heat during the asccnt, down to a depth of 2,700 feet. Beyond this point the increase was not so marked. At a depth of 3,000 feet the temperature was 177, giv ing an increase of one dogree for evcry iwenty-three feet bored. YVater first began to well up at a depth of 3,070 ieet, itsteuiperature then being 110. Froin this point onward the quantityand temperature of the water rapidly increa.-ed. Thus at 3,092 feet its temperature had risen to 150, and tin yield in twenty-four hours, frotn U,500 to 44,500 gallons. Fioally, when the boriüg had reachfd 3,200 feet, at which point il was stopped, the temperature of the water as it barst froui the orifice of the tube was 165, and the quantity 272,000 gallons in the twenty-four hours. The yield was afterward redueed to 167,200 gallons, in consequence of the bore being lined with wooden tubes, which redueed its diameter. The waterdisengagescarbonicacidinabundance, and it also contaius nitrogen and a Hule hulphuretted hydrogen, besides aome fixed matter, chiefly sulpbates and carbonates of potash, soda, lime and magnesia. If we blow a fire it burns more üercely but if we blow a candle it goes out. These two facts taken together are a familiar illubtration of the influence of temperature upon chemical affinity. In both cases, that of the fire and the candle, the burning ib the combining of carbon and hydroen with oxygen. Now cold carbon or hydrogen maj lie in contact with oxygen for any length o: time without combining with either, but i the substances are made red hot they instantly enter into chemical combination. When a candle is burning, the heat generaled by the combustión constantly raises new quantitiea of the material to the temperature at which combination with oxvc" _:u i.i - ri - , i ii.u inc uoiuDustion in kept up. But if a current of air of a temperature far below the oombus tion point is thrown against the flame, the hot var-ors are swept away, and other whicl are ri.-ing in their place are to cooled that combination with oxygen no longer contin ues ; in other words, the candle ceases to to burn. Onthe other hand when we blow a large fire, the mass of burning combustión is so great, that in.-ti ad of the carbon arn hydrogen being cooled, the oxygen is heat ed, and the couibination is made more act ive ; in other words, the fire burns more fiercely. An influence of the two great planets, Ju piter and Saturn, on the phenomena o rarthquakesappears to have been establii-li d by M. Delauney. Taking for data M AKxis Perrey's tables truua 1750 to 1S42 nd ncting the niuxima of thecurve obtain ed, hu finds a first group of maxima coiu incticing in 1759, and having a period o about twelve ytar.s; a sec' nd oonjmenciQi ii 1756, also wiih a period of' welve jears and a ihird and f'ourlh group c ■uimeiniiiL m 1756 and 1773 respectively, and paol having a period of twenty-eight ycars. Nuw ihe epoche of maxima of the first and sec nd aroups coincide with the epochs whci JupitiT attains his mean longitudes of 265 mu 135, while the epochs of maxima ot lie tlnrd and fourth groups oorrespond bo he times when Saturu il founcj at the simr o longitudes. Tlmsarthquakesseem to MM thriiiiiíli a maxi in uní win n J upiter anti Saturn are in the nniiihborhood of the mean ongitudes 265 and 135. M. Dejauney urther thinks this influence is duo tó paar iges of these two platiets through condjíc itroaius of meteors. He givea an approxinate taljle of future earthquakes, indicatnir partirularly the years 1886, 1891, 1888, 1900, 1912, 1919, 1927 aud 1930 as having lumerous earthquakes. The extraordinary statement that Mr. [tobert Packer whie traveling in Nebraska, liad covered with his wife and friend at bis home at Sayre, Pa., by means of a tel;phone, though a distance of 2,000 miles intervened, is thus modih'ed by the Scien:ific American : " We now learn, on good luthority, that though Mr. Pucker'.s frionds received his communication by telephone, t was not so senl by M. Packer. The mes ■age was sent from Nebraska to Mauch Dhunk, Pa., by telegraph ; thence it was x'legniph.'d to the Sayre office of the Pennsylvania Canal & Kailroad Company, of whioh Mr. Packer is superintendent, and ('rom there it was transmitted to Mr. Pack ;r's house by telephone, falling ehort of :ho report of the telephone's performmco by some 1199 miles and a fraction." The extent to whioh water uiingles with bodies apparcntly the most solid is very (tonderful. The glittering opal, which beauty wears as an ornament, is only flitit ind water. Of every 2200 tons of earth tvhich a landholder has in his estáte, 400 are water. The snow-capped summits of SnowioD and Iieo Nevis bave inany million tons jf wuter in a .olidified form. In every piaster of Paris statue whieh an Italian carries through the streets for sale there is one pound of water to every four pounds of elialk. Various lubricating materials are naod to limi the loss of power through friction. Where polished steel moves on steel, or pewter properly oiled, the friction is about ne-íbrutli of Un weigln ; on copper or lead ne-filth ; ou brasa, one-sixlli. Briquettes, or coojpressed fuel of .-malí r waste coal are now manufactured ncar ne of the Kngli-h ni nos at a cost of a hilling a ton. They are nn excellent fuel, and have loug bren used in Fraoce.