Vol. XXII. So. 10.] 



POPULAE SCIENCE NEWS. 



149 



Practical Cbemtetrp atiD t^e 'Sivts. 



NICKEL AND COBALT: THE TWIN METALS. 



AuouT the middle of the last century two 

 new metals were discovered at nearlj- the same 

 time, and so closely' related to each other that 

 they may appropriately be called the twin 

 metals. Nickel and cobalt are the only two 

 elements known which possess the same 

 atomic weights ; for although the latest inves- 

 tigations seem to show a slight difference in 

 this respect between them, yet it is in any 

 case only a fraction of a unit, and the number 

 59 is apparently the nearest certain determi- 

 nation yet made of the atomic weight of 

 either. 



Dr. Crookes remarks that so close is the 

 similarity between these metals, they might 

 even yet be considered one substance if cer- 

 tain of their salts were not differently colored ; 

 and every student of chemistry knows that 

 their complete qualitative or quantitative sep- 

 aration is a^ost difficult and unsatisfactory 

 task. Both are magnetic, especially nickel ; 

 in this respect, as in some others, resembling 

 iron. 



Cobalt is of considerable value in the arts, 

 on account of the brilliant and permanent 

 colors of some of its salts. When a com- 

 pound of cobalt is fused with silica and pot- 

 ash, a glass of a magnificent blue color is 

 formed, known as smalt. This is finely pul- 

 verized, and used as a pigment. It has lately 

 been replaced, to a considerable extent, by 

 the cheaper artificial ultramarine ; but, unlike 

 that substance, its color is not bleached by 

 acids. Salts of cobalt are also used to obtain 

 a blue color in glass and china painting. 



Cobalt yellow is a nitrite of cobalt and pot- 

 ash. It is one of the few salts that can be 

 prepared free from nickel and other impurities, 

 and on this account is important from a chem- 

 ical stand-point. 



Nickel is a much more valuable metal than 

 its associate. It has a brilliantly- silver-white 

 color, is stronger than iron, has great resist- 

 ance to chemical agents, and does not rust 

 when in contact with air or water. It forms 

 with other metals many valuable alloys, in- 

 cluding the well-known german silver, — an 

 alloy of copper, zinc, and nickel. Some of 

 the smaller coins of this country are composed 

 of nickel and copper. Laboratory vessels of 

 pure nickel have recently been introduced, 

 and for many purposes are a cheap and satis- 

 factory substitute for platinum. 



Metallic nickel is usually sold in the form 

 of small cubes. The oxide of nickel is first 

 prepared and made into a paste with oil, 

 starch, charcoal, and otherreducing substances. 

 The cubes are formed from ihis paste, and 

 strongly heated, till the oxide is reduced. 

 The metallic nickel does not melt, but sinters 

 together till the resulting mass is quite com- 

 pact. 



The most important use of nickel, however, 

 is in the art of electroplating. By this means 

 a bright silvery coating ma3' be deposited, 

 which will not tarnish or rust. The process 



is the same as in silver or gold plating. A 

 solution of a nickel salt is prepared, and the 

 article to be plated is attached to a wire carr}- 

 ing an electric current, and immersed in the 

 solution. A plate of nickel is attached to 

 another wire connected with the same electric 

 circuit, and also placed in the solution. As 

 the current passes through the liquid, metallic 

 nickel is deposited in an even coating, which 

 may be made of any desired thickness, and 

 onl^- needs a slight polishing to give it the 

 familiar brilliant lustre. 



To the chemist the occurrence of these 

 twin metals, so nearly alike, and yet perfectly 

 distinct forms of matter, suggests many inter- 

 esting questions. We can no more change 

 nickel into cobalt than we can transform mer- 

 cury into gold, as the old alchemists claimed. 

 Still, we cannot help thinking that the almost 

 identical chemical and physical properties may 

 be a hint of a possible evolution, in some dis- 

 tant i)eriod of the history of the universe, of 

 the diflTerent elements from one primordial form 

 of matter, in which the differentiation of 

 cobalt and nickel was, bj- some unknown 

 cause, arrested at an earlier period than that 

 of the more dissimilar metals. Whatever this 

 process of evolution may have been, it cer- 

 tainly ceased long ago, and the elements re- 

 main unaltered as thej' came from Nature's 

 laborator}-. In the ever-widening field of 

 spectroscopic analysis we have already found 

 some help towards the solution of the prob- 

 lem, and it may not be many j-ears before the 

 whole matter will be made clear to us. 



KERKOOK PETROLEUM SPRINGS, ASIA 

 MINOR. 



On the eastern side of the Tigris, in the neigh- 

 borhood of Kerkook, are numerous petroleum and 

 naphtha springs which furnish employment for 

 many of its people. The most abundant supply 

 is obtained from the hills around, but a good deal 

 is collected on the surface of the water in the 

 ditches and stagnant pools. Some years ago this 

 petroleum wa.s largely used in Bagdad and Busso- 

 rah; but, as the natives do not understand how to 

 refine it properly, it has of late years been super- 

 seded by Russian and American oil. If the proper 

 scientific methods were used in refining it, it is 

 probable that the oil from this region might become 

 of great commercial importance, as it is inexliausti- 

 ble in quantity, and, even without a railroad, trans- 

 portation is easy by way of the Tigris and Persian 

 Gulf to Bagdad, Bussorah, India, and beyond. 

 There is, it is said, no limit to the supply which 

 might be procured from the hills about Kerkook and 

 Arbela. These have been yielding bitumen and 

 petroleum since the time of Alexander the Great at 

 least, in whose honor Arbela was illuminated after 

 his great victory over the Persians. The petroleum 

 springs from almost every hollow in the hills. As 

 it rises from the earth it is of a brownish color with 

 a greenish tinge. It quickly becomes opaque and 

 hard, in which state it is easily broken, with a shin- 

 ing, resinous fracture. The natives use it for fuel 

 to burn limestone, and also to cover boats with. 

 The boats which are covered with this substance 

 look as if they were covered with a thick hide. 

 Mr. Grattan Geary thus describes the principal 

 spring, a funnel-shaped hollow ten or twelve yards 

 in diameter: "The hollow is filled with a dark 

 blackish-brown substance, from the centre of which 



salt-water bubbles up, and escapes to some salt- 

 ponds, where, evaporating, its saline matter is left 

 behind. Sometimes the water rises at intervals 

 from the centre in jets a foot and a half high, aud 

 at others it bursts out in a considerable volume, 

 raising the petroleum into huge bubbles, which 

 burst, and let the imprisoned water out with a gur- 

 gling noise. The pit is very deep in the cen- 

 tre, but its shallowness at the edges permits the 

 people to stand in it up to their knees, while they 

 with facility roll up the tenacious substance into 

 masses which are carried away and placed to dry 

 in the heat of the sun. AVhen hardened it is used 

 chiefly for fuel for the burning of limestone. The 

 flames give a strong light and heat, and it leaves a 

 small earthy residue after it is burned. Notwith- 

 standing the quantity that is constantly drawn off, 

 the petroleum always continues at the same level, 

 and the Hittites say the supply in the pit is inex- 

 haustible. The fluid skimmed off the water in the 

 ditches and marshy places in the neighborhood of 

 Kerkook is of a blackish-green color, and smells 

 abominably." ■ — Enylnee.ring and Mining Journal. 



WINDMILLS FOR ELECTRIC LIGHTING. 



" SoMK time ago the possibilities of windmills 

 for domestic electric lighting were mentioned in 

 this journal, aud lately the experiment has been 

 practically tried. Professor Blyth read before the 

 (ilasgow Pliilosophical Society a paper on the 

 subject, in which he describes an experiment 

 which he made last summer, — the lighting of a 

 cottage in which he spent his vacation by a 

 dynamo driven by a windmill, and charging a 

 storage battery. The windmill used w.is an old- 

 fashioned style, with four arms at right angles to 

 each other, each of them thirteen feet long. There 

 was no especial regulating device. The dynamo 

 was belted directly to the fly-wheel of the mill, 

 and charged twelve cells of storage battery, which 

 supplied the incaudescent lamps in the cottage. 

 Professor Blyth had never used more than ten 

 lamps at once, but he could have used more. 

 With a good breeze, enough electricity could be 

 stored in half a day to supply light for four even- 

 ings of three or four hours each. The lamps used 

 were of eight-candle power. When charging, the 

 current passed througli a cut-out that would dis- 

 connect them from the dynamo when it ran below 

 a certain speed : so the windmill could be allowed 

 to run all the time, charging the battery when the 

 wind happened to be strong enough. The current 

 had been used to run a light turning-lathe, and 

 Professor Blyth had begun to make a light carriage 

 to be run by the stored electricity. The paper 

 opens to us a field for ingenuity, comfort, and 

 amusement in our homes. Windmills much 

 superior to that described can be readily pur- 

 chased, a small dynamo can be bought or built at 

 little cost, and storage batteries can be purchased 

 or made. With them we could light our house 

 econondcally ; our light would be better, cooler, 

 and healthier than gas or coal-oil lamps; while the 

 current could be utilized for running fans, sewing- 

 machines, etc. Indeed, to the average American, 

 with some spare time and some small ingenuity, 

 the amusement and instruction of such a plant 

 would more than pay for its expense." — Science. 



ASSOCIATION OF HYDROCARBONS WITH 

 RpCK-SALT IN NATURE. 



The frequent association of salt and bitumen 

 or petroleum in the same deposits has often struck 

 me as likely to lead to the development of some 

 probable theory as to the formation of these hydro- 

 carbons. Almost all specimens of rock-salt, when 



