334 



SCIEXCE. 



[Vol. VII., No. 166 



from the other monographs which have thus far 

 emanated from the geological survey, Mr. Lord 

 has given an extremely interesting story of the 

 discovery and development of what is doubtless 

 the richest mineral lode in the world, as well as a 

 vivid picture of the life in the town which sprung 

 up with such surprising rapidity beside it. The 

 book is one which can but be read with enjoy- 

 ment and profit by all, no matter what their idea 

 is of the proverbial dryness of government reports. 



On the loth of May. 1849, William Prouse, a 

 young Mormon, travelling up Carson valley, 

 made the first discovery that gold existed in what 

 is now western Nevada. The region is a barren 

 desert, occupying the eastern slopes of the Cor- 

 dilleras, too arid to support more than the barest 

 vestiges of life ; and yet the report of the few 

 grains of yellow dust discovered there by Prouse 

 was sufficient to attract into it hosts of eager men 

 from already overcrowded California. For ten 

 years prospecting went on in and about what was 

 early named Gold Canon, with varying success. 

 Sands were washed for gold with profit in many 

 places, but no one as yet suspected the mine of 

 wealth which lay at then very door. In June, 

 1859, Henry Comstock, a Canadian miner, secured 

 a claim on the side of Sun Peak (now Mount 

 Davidson), and thus impressed his name forever 

 on the richest silver-lode ever opened. Still it 

 was supposed that only gold was to be found, un- 

 til a fortunate assay of some of the black gangue, 

 which the miners had always thrown away as 

 worthless, showed that it contained $3,000 in sil- 

 ver and $876 in gold to the ton. From this dis- 

 covery (July, 1859) the development of the real 

 richness of the Comstock may be said to date. 



Nothing more was needed to start a vast tide of 

 emigration from California to the Washoe. Over 

 the almost impassable mountain-trail struggled, 

 in the early spring of 1860, the wild rushing mass 

 of humanity, without proper food or clothing. 

 Freight-transportation was almost impossible, and 

 into the desert they hurried, with no thought but 

 to be first at the pile of treasure which all ima- 

 gined must be awaiting them. 



For a picture of the wild life of the mining- 

 camp ; of the endless litigation over claims ; of the 

 rapid growth of camp to town, and of town to 

 city, as the mines developed : of the almost super- 

 human feats of energy and endurance in strug- 

 gling with fire and water and in competition with 

 each other, — we must refer the reader to the 

 work itself. The lode proved richer at every 

 point than the most sanguine prospector had at 

 first imagined. Millions were spent for machinery 

 and in draining and ventilating the mines, and yet 

 the supplies of riches seemed endless. 



In 1869 a railroad was actually constructed to 

 this mountain fastness ; and just about this time 

 the mines, which had been increasingly produc- 

 tive for ten years, showed their first signs of ex- 

 haustion. Many of the old ore-bodies had almost 

 ceased to produce. In 18T2 a panic in Washoe 

 mining-stocks ensued, which caused them again 

 to change hands and as rapidly to bring fortune 

 to their possessors. In 1873 was discovered the 

 so-called ' Big bonanza.' No other such enormous 

 mine of wealth has ever been uncovered in the 

 earth's crust. The shafts were sunk lower and 

 lower, but the ore only seemed to increase in rich- 

 ness with the depth. The silver production of the 

 lode, which was fourteen millions in 1866, and 

 six millions and a half in 1870, rose to over 

 thirty-eight millions in 1876. 



But of the details of this wonderful tale there 

 is no space to enter here. For its romance and its 

 fact alike we must refer the reader to the vivid 

 descriptions and the statistical tables of Mr. Lord. 



The work of Mr. Curtis on the silver deposits of 

 Eureka, which lies to the eastward of the Com- 

 stock Lode, in central Nevada, is altogether differ- 

 ent in its aim and scope from that of Mr. Lord. 

 It is no story of mining and miners, but a clear 

 discussion, from an engineer's point of view, of 

 the nature and origin of the deposits, and an ac- 

 count of the methods by which they are worked. 

 Only enough geology is borrowed from the forth- 

 coming report of Mr. Arnold Hague to make the 

 occurrence of the ore intelligible. 



The deposits are large, irregular masses embed- 

 ded in a limestone of Cambrian age. This is ac- 

 companied by other limestone and quartzite beds 

 of the same and later age, and by acid eruptive 

 rocks. The ores are mainly sulphurets of lead 

 and silver, the former of which, however, has 

 been oxidized down to a certain depth. The de- 

 posits occupy caverns in the limestone which they 

 never completely fill. 



The author thinks it probable that the rocks 

 were first disturbed by dynamic forces, which 

 crushed the limestone more than it did the other 

 beds. Into this penetrated heated alkaline solu- 

 tions, coming from below, which deposited the 

 silver and lead sulphides as soon as the conditions 

 of heat and pressure necessary for their solution 

 were removed. There seems to be no evidence 

 that the ore was derived in any way from the sur- 

 rounding rocks. The only reason why it is found 

 in the limestone is because the more shattered 

 condition of this rock offered more opportunity 

 for the circulation of the mineral solutions. The 

 author also thinks that the cavities now occupied 

 by the ore did not exist before its deposition, 

 but that they were formed by a removal of the 



