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bCIKiMCE. 



[Vol. XX.. No. 509 



SCIENCE: 



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WHY IS SEA.-WATER SALT? 



BY W. MATTIEU WILLIAMS, F.R.A.S. , F.C.S., LONDON, ENGLAND. 



This question has been regarded as a mystery and has given 

 rise to some curious speculations, but a little consideration of the 

 subject must, I think, satisfy us all that it would be very won- 

 derful, quite incomprehensible, if the waters of the ocean were 

 otherwise than salt as they are. 



The following explanation was first suggested to myself many 

 years ago when receiving my first lessons in practical chemical 

 analysis. The problem then to be solved was the separation of 

 the bases dissolved in water by precipitating them, one by one, in 

 a solid condition; filtering away the water from the first, then 

 from this filtrate precipitating the second, and so on, until all were 

 separated or accounted for. 



But in doing this there was one base that was always left to 

 the last, on account of the difficulty of combining it with any 

 acid that would form a solid compound, a difficulty so great that 

 its presence was determined by a different method. This base is 

 soda, the predominating base of sea-salt, where it is combined 

 with hydrochloric acid. Not only is soda the most soluble of all 

 the mineral bases, but the mineral acid with which it is combined 

 forms a remarkably soluble series of salts, the chlorides. Thus 

 the primary fact concerning the salinity of sea-water is that it 

 has selected from among the stable chemical elements the two 

 which form the most s^oluble compounds. Among the earthy 

 bases is one which is exceptionally soluble, — that is, magnesia, — 

 and this stands next to soda in its abundance in sea-water. 



Modern research has shown that the ocean contains in solution 

 nearly every element that exists upon the earth, and that these 

 elements exist in the water in proportions nearly corresponding 

 to the mean soluhility of their various compounds. Thus gold 

 and silver and most of the other heavy metals are found to exist 

 there. Sonnenstadt found about 14 grains of gold to the ton of 

 sea-water, or a dollar's worth in less than two tons. 



As the ocean covers all the lower valleys of the earth, it receives 

 all the drainage from the whole of the exposed land. This drain- 

 age is the rain-water that has fallen upon this exposed surface, 

 has flowed down its superficial slopes, or has sunk into porous 

 land, and descended under-ground. In either case the water 

 must dissolve and carry with it any soluble matter that it meets, 

 the quantity of solid matter which is thus appropriated being pro- 

 portionate to its solubility and the extent of its exposure to the 

 solvent. Rain when it falls upon the earth is distilled water 

 nearly pure (its small impurities being what it obtains from the 

 air), but river-water when it reaches the ocean contains measura- 



ble quantities of dissolved mineral and vegetable matter. These 

 small contributions are ever pouring in and ever accumulating. 

 This continual addition of dissolved mineral salts without any 

 corresponding abstraction by evaporation has been going on ever 

 since the surface of the earth has consisted of land and water. 



An examination of the composition of other bodies of water, 

 which, like the ocean, receive rivers or rivulets and have no other 

 outlet than that afforded by evaporation, confirms this view. All 

 of these are more or less saline, many of them more so than the 

 ocean itself. On the great Table Land of Asia, " the roof of 

 the world," there is a multitude of small lakes which receive the 

 waters of the rivers and rivulets of that region and have no outlet 

 to the ocean. On a map they appear like bags with a string 

 attached, the bag being the lake and the string the river. All 

 these lakes are saline, many of them excessively so, simply be- 

 cause they are ever receiving river-water of slight salinity and 

 ever giving off vapor which has no salinity at all. There is no 

 wash through these lakes as in the great American lakes or those 

 of Constance, Geneva, etc. 



The Sea of Aral and the Caspian are lakes without any other 

 outlet than evaporation, and they are saline accordingly. The 

 Dead Sea, which receives the Jordan at one end and a multitude 

 of minor rivers and rivulets at its other end and sides, is a noted 

 example of extreme salinity. It is, as everybody knows, a sea or 

 lake of brine. The total area of land draining into the great ocean 

 does not exceed one-fourth of its own area, while the Dead Sea 

 receives the drainage and soluble matter of an area above twenty 

 times greater than its own, and thus it fulfils the demand of the 

 above-stated theory by having far greater salinity than has the 

 great ocean. 



According to this view the salinity of the ocean must be steadily 

 though very slowly increasing, and there must be slowly proceed- 

 ing a corresponding adaptation or evolution among its inhabitants, 

 both animal and vegetable. The study of this subject and the 

 effect which the increasing salinity of the past must have had 

 upon the progressive modifications of organic life displayed by 

 fossils is, I think, worthy of more attention than it has hitherto 

 received from palaeontologists. 



THE ENERGY-FUNCTION OF THE MAGNETIC CIRCUIT. 



BY CHAS. P. STBINMBTZ. 



In designing alternate-current electric motors, in October, 1890, 

 I was confronted by the problem, to calculate the loss of energy 

 caused by the reversals of magnetism in the iron of the motor- 

 field. At that time very little was known on this phenomenon 

 besides a few experimental data of Ewing. From these data 

 mathematical analysis yielded the result that the loss of energy 

 (by conversion into heat) during a complete cycle of magnetiza- 

 tion is proportional to the 1.6 power of the intensity of magneti- 

 zation, or magnetic induction, B ; that is, can be expressed by the 

 formula : — 



H=7,B,'-<' 



where H is the loss of energy per magnetic cycle, and tj a "co- 

 efficient of hysteresis." This result was published in the Electrical 

 Engineer, New York, December, 1890. 



But it was not quite satisfactory, in so far as Ewing's determina- 

 tions were made by the magnetometer method, with very slow 

 cyclic variations of magnetism, and it was doubtful whether for 

 very quick cycles, as they take place under the influence of an 

 alternate-current of 100 or more complete periods per second, the 

 same law holds, and especially the co-efficient of hysteresis, ij, is 

 the same. 



A great number of tests, made during the year 1891, partly by 

 the three electrodynamometer method, partly by the use of the 

 Eickemeyer differential magnetometer, and published in a paper 

 read before the American Institute of Electrical Engineers, Jan- 

 uary, 1892, proved that up to over 200 complete magnetic cycles 

 per second the loss of energy per cycle — by conversion into heat 

 — is constant and independent of the number of cycles per second, 

 following the law of the 1.6 power; while, when under the in- 

 fluence of the alternating magnetism, Poucault — or eddy — cur- 



