118 



POPTJLAR SOTEWCE TTEWS. 



[August, 1888. 



of it can be broken by the hand: this alloy closely 

 resembles metallic zinc in its physical properties. An 

 addition of but two-tenths or three-tenths per cent of 

 tellurium to bismuth will alter the form of the crys- 

 tals which the latter metal forms upon cooling from 

 the melted state. Black and red sulphide of mer- 

 cury are chemically the same, though differing so 

 widely in appearance. Lead can be thrown down 

 by electrolysis in such a condition that it will 

 readily oxidize in air, and turn yellow ; and copper 

 cau be so thrown down electrolytically as to pre- 

 sent properties differing totally from those which 

 it exhibits under ordinary conditions. Sulphur 

 and phosphorus may, after melting, be cooled down 

 below their melting-points without solidifying. He 

 dropped a solid piece of phosphorus into some phos- 

 phorus so cooled down, and immediately the whole 

 mass solidified. Somewhat the same phenomenon 

 is presented by melted gold. He took some but- 

 tons of melted gold, allowed them to cool to a cer- 

 tain point, then touched them with a rod: the 

 effect was, to momentarily raise their temperature, 

 and make them glow ; then they solidified. Joule, 

 he said, had proved that, when iron is released from 

 its amalgam with mercury, it will take fire on 

 exposure to the air, and that several other metals 

 behave in the same way. 



Aluminum and mercury, he continued, have 

 normally little affinity for oxygen. His demon- 

 strator, Mr. A. Haddon, here took a plate of alumi- 

 num, placed it in a dish, and began to rub mercury 

 over it. After the lapse of several minutes, the 

 surface amalgam of the two metals began to turn 

 dead- white in the air; and on inverting the sheet, 

 and tapping it, a small cloud of pure white clay 

 fell from its surface. Next Mr. Roberts-Austen 

 half filled a flask with powdered bismuth, lead, and 

 tin, poured mercury upon the mixture, and placed 

 the flask upon a wet board. As the powders dis- 

 solved in the mercury, sufficient cold was produced 

 to freeze the flask to the board. Mr. Spring of 

 Liege had attempted to explain this phenomenon 

 on the hypothesis that the metallic molecules so 

 rearranged themselves as to occupy more space 

 than before, and the act of expansion of the mass 

 produced the low temperature. 



The speaker next drew attention to a new alloy 

 of platinum and gold upon which he had been 

 working for some time. When thrown into water, 

 it took fire; and the gold is released as a black 

 powder, differing from ordinary gold in its proper- 

 ties, for it readily forms auric hydride. By heating, 

 it turns into a dull-yellow powder, and by addi- 

 tional heating, forms normal metallic gold. The 

 Japanese, he said, had long utilized this abnormal 

 form of gold, which they obtained from its alloy 

 with copper, with which latter they formed orna- 

 mental metallic designs upon knife-handles and 

 such things, and then released the dark-colored 

 gold by a pickling process; by its means they had 

 produced an appearance of transparency in a 

 metallic representation of water, at a place where 

 in the design a duck was represented plunging 

 half its body below the surface of a stream. He 

 believed that no other nation had made use of this 

 alloy. 



The changes which small proportions of foreign 

 matter will produce in metals are not necessarily of 

 small practical importance, for a small fraction of 

 bismuth in copper will reduce its electrical con- 

 ductivity sufficiently to cause any submarine cable 

 made with it to become a commercial failine. A 

 cable made of the copper of to-day has twice as 

 much message-carrying power as a cable made in 

 the early days of telegraphy, because of the copper 

 now used being purer. Pure gold has a breaking- 

 strain of from sixteen to seventeen tons to the 

 square inch ; but when alloyed with but two-tentlis 



per cent of lead, it will break with a slight blow or 

 under a trifling strain. He next exhibited an alloy 

 of zinc and rhodium which possessed in a small 

 degree some of the properties of gun-cotton. — 

 Scientific American Supplement. 



FACTS ABOUT RAILROADS. 



From an interesting little folder issued by the 

 publishers of Scribner's Magazine we glean the fol- 

 lowing items. We may mention, in passing, that 

 the special railroad articles now in course of pub- 

 lication in this magazine are of the greatest inter- 

 est 'and value, and are a notable example of the 

 highest class of modern magazine literature. 



There are 150,600 miles of railroad in the United 

 States, which is about half the mileage of the 

 world. The total cost was $9,000,000,000, and 

 over 1,000,000 persons are employed by them. 

 The longest mileage operated by a single company 

 is that of the Atchison, Topeka, and Santa Fe 

 Railroad, about 8,000 miles. The Canadian Pacific 

 extends from Quebec to the Pacific Ocean, and ex- 

 tends farther east and west than any other road. 

 The largest number of passengers is carried by the 

 New York Elevated Railroad, — 525,000 a day, or 

 191,625,000 every year; and of the passengers car- 

 ried by all the roads in the country, only one in ten 

 million is killed. The chances of being struck by 

 lightning are much greater than of being killed by 

 a railroad accident. 



The longest single span of a bridge in this couu- 

 try is that of the new Poughkeepsie bridge over 

 Hudson River, 548 feet ; the highest bridge is 

 the Kinzua viaduct on the Erie road, 305 feet; 

 the longest tunnel is the Hoosac in ^Massachusetts, 

 4| miles; and the highest point reached by a rail- 

 road in the United States is 10,852 feet, or over 

 2 miles, at Marshall Pass, on the Denver and Rio 

 Grande road. 



The average cost of a mile of railroad is about 

 $30,000. A sleeping-car is worth $15,000, or $17,- 

 000 if " vestibuled : " and a first-class engine costs 

 $8,500; but, as an engine is capable of earning 

 about $100 a day, it ought to pay a good interest 

 on the investment. The first locomotive was built 

 in this country by Peter Cooper of New York. 

 With ordinary wear, a steel rail will last eighteen 

 years; so that, practically, the entire railroad sys- 

 tem of the world must be renewed six or seven 

 times in a century. 



The fastest time made by a train is a matter of 

 much dispute; but it was probably accomplished 

 on the Philadelphia and Reading Road, where 92 

 miles were traversed in 93 minutes, a single mile 

 being run in 46 seconds, or at the rate of 77^ miles 

 per hour. The fastest long-distance time was 

 made by a special theatrical train in June, 1886, 

 between Jersey City and San Francisco, in 3 days 

 7 hours 39 minutes and 16 seconds. 



We may also remark, in closing, that the service 

 and accommodations on the American railroads are 

 superior to any in the world, and that the average 

 fares are much lower. 



PROCURING CHEMICALS UNDER 

 DIFFICULTIES. 



In France the railroads and other private enter- 

 prises are "regulated " by the government to an 

 extent which would surprise even an American 

 legislator. The beauties of such a system aie well 

 illustrated by the following incident, related by a 

 distinguished French practitioner in the Gazelle des 

 liopitaux : — 



" Some days ago, wishing to use the yellow, 

 fuming, monohydrated nitric acid, I applied to my 

 druggist for the same. He informed me that he 



had none. I then requested him to send for a 

 small amount — ten grams — in a vial with a 

 ground stopper. Yesterday he had not received 

 the nitric acid, but, instead, the following note from 

 the Pharmacie Centrale of France : — 



" ' According to the police regulations governing 

 railroads, monohydrated nitric acid cannot be 

 carried except in a special armor-plated car fur- 

 nished by the sender ; on this account your order 

 cannot be filled.' 



" Imagine my poor ten-gram vial of nitric acid 

 in an armor-plated car! " 



WORKSHOP HINTS. 



To MAKE Varnish Adhere to Metal. — Add 

 five-hundred ths of one per cent of boracic acid to 

 the varnish. 



Old Oil. — Oil seems to wear out by long-con- 

 tinued use, and to lose to some extent its lubricat- 

 ing qualities. It has been suggested, as a reason 

 for this, that the minute spherical globules of which 

 the oil is conceived to be made up, become flattened 

 by the wear and pressure, and so do not slide and 

 roll over each other as easily as before. 



Simple Dead Finish. — For a simple but not 

 very solid dead finish for walnut, proceed as 

 follows : Take equal parts of burnt umber and 

 finely ground pumice-stone; mix them together. 

 Apply with a woollen rag or hair-cloth dipped in 

 raw or boiled linseed oil. Clean with soft old 

 cotton rags. The longer and harder the rubbing, 

 the better the results. You need not fill or oil 

 the walnut. 



Delta-Metal. — An alloy of copper, zinc, and 

 a small quantity of iron is called delta^metal. It 

 possesses the properties of blacksmith's iron, is 

 strong as steel, and of a golden-yellowish color. 

 Toward acids and sea-water it is very resisting, 

 and does not rust, nor does verdigris form on it. 



Manhole Gaskets.. — On opening a boiler, much 

 trouble is often experienced from the tearing of the 

 manhole gaskets. This may be avoided by putting 

 a little white lead on the face of the gasket that 

 rests on the manhole plate, and by chalking heavily 

 the other face of the gasket, as also the part of the 

 manhole frame with which it comes iuto contact. 

 On subsequently opening the boiler, the gasket will 

 generally be found to adhere firmly to the plate, 

 and to separate from the frame without tearing. 



To Clean Small Screws. — Screws that are 

 too small for separate treatment may be cleaned 

 from rust as follows : Take a pound of screws 

 and place them in a small box — a cigai'-box will 

 do; put a small quantity of oil on them, and shake 

 for a minute ; then put a piece of cotton- waste in 

 the box, and repeat for a minute; finally put a 

 handful of sawdust in the box, and shake for 

 another minute or so, and remove the sawdust by 

 sifting it from the screws in a fine sieve. 



Iron Cement. — The cement known as "iron 

 cement " is lequired to withstand a high tempera- 

 ture, and act as a good conductor of heat, while 

 making a sound joint. Mr. P. J. Grouvelle of 

 Paris has patented a new kind of iron cement, in 

 which a better conductor of heat is substituted for 

 a portion of the cast-iron filings in the usual mix- 

 tures. A suitable mixture, he tells us, may contain 

 sixty-two parts of cast-iron filings, thirty-two parts 

 of gun-metal or copper filings, and six parts of a 

 four per cent solution of glacial acetic acid, with 

 sufficient water to render the mixture moist. 



Cherry Stain. — Mix together, by stirring, one 

 quart of spirits of turpentine, one pint of japan, 

 one pound of Venetian red ground in oil, and two 

 ounces of dry burnt umber. Apply with a brush, 

 and wipe off with a cloth. Finish with one coat of 

 shellac and two coats of varnish. 



