301: Scientific Intelligence. 



comes to us in a new edition with all the merits of the old well- 

 attested by a wide usage in the colleges of the land. As the 

 author set forth to do in the preface to the first edition, he has 

 succeeded in doing: viz. the making of a work " which shall be 

 both interesting and profitable to the intelligent general reader, 

 and at the same time a suitable text-book for the higher classes of 

 our colleges." 



Some additions as well as changes in the arrangement have been 

 made, -the most important of which are " a fuller discussion of the 

 difficult subject of earthquakes^ in the light of the recent investi- 

 gations of Milne, Dutton, Seebach and Schmidt ; a brief account 

 of the origin of varieties of igneous rocks by differentiation of 

 rock-magmas^ made necessary by the writings of Iddings and 

 others; a greater emphasis on the Cambrian as a subdivision of 

 the Palaeozoic; the latest results of Walcott, Matthew, and 

 Beecher on the structure and affinities of Trilobites : the latest 

 results of Marsh, Cope, Osborn, Scott, and Wortman on the struc- 

 ture and affinities of Mesozoic reptiles and Mesozoic and Tertiary 

 mammals / some clearer statement on the subject of the causes of 

 the glacial climate y and a brief discussion of the causes of geol- 

 logical climates in general." 



6. On the amount of gold and silver in sea-w ater.— Proi. A. 

 Liversidge has carried on a series of experiments made with the 

 object of determining the amount of gold in the sea-water off the 

 coast of New South Wales. The method of Sonstadt (Chem. 

 News, 1872, pp. 159, 160 and March 11, 1892) was employed. 

 After detailing the separate experiments and remarking that the 

 amount of gold found must necessarily be less than the total 

 amount present in the water, the author concludes that all the 

 " evidence is in favor of gold being present in sea-water off" the 

 New South Wales coast in the proportion of about '5 to 1 grain 

 per ton, or in round numbers from 130 to 260 tons of gold per 

 cubic mile. This of course means an enormous amount for the 

 whole of the ocean, the cubic contents of which used to be put 

 down at 400,000,000 cubic miles, and if the gold be uniformly pres- 

 ent at the rate of 1 grain per ton the total amount would be over 

 100,000,000,000 tons of gold; a later estimate is 308,710,679 cubic 

 miles; this even would mean over 75,000,000,000 tons of gold. 

 But at the present day it would probably not pay to extract the gold 

 by itself, although it might as a bye-product in the manufacture of 

 salt, bromine, etc. The enormous amount of gold in the sea is, 

 however, probably very small in comparison with the amount 

 scattered through sedimentary and crystallized rocks, i. e., apart 

 from gold in veins and other deposits." He adds further that all 

 the sea-waters gave some silver, usually from one to two grains 

 per ton, but the scorification and cupellation process were lacking 

 in the necessary precision for the exact determination of silver in 

 such minute quantities as it exists in sea- water. 



A subsequent article discusses the supposed removal of silver 

 and gold from sea-water by Muntz metal sheathing. The results 



