572 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



doubt. Before another year we shall doubtless be able to 

 record the success or failure of the experiment which Cap- 

 tain Eads has pushed forward with such admirable perse- 

 verance and energy. The act of Congress relating to this 



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work, it will be remembered, provided that the same should 

 be undertaken at the risk of the contractor; and that pay- 

 ments should be made of specified sums in instalments as 

 rapidly as a channel of specified depth and width should be 

 obtained the completion of the work being based on the 

 obtaining of a channel thirty feet in depth and two hundred 

 feet in width, for maintaining which permanently a specified 

 yearly payment is also provided for. 



THE SUTRO TUNNEL, 



the approaching completion of which we noted in last 

 year's Record, together with a brief outline of the character 

 and magnitude of the work, reached the Comstock Mines 

 during the past year, connection with the 1650 -foot level 

 of the Savage Mine having been effected on the night of 



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July 8, 1878. Much remains to be done before the objects 

 of its projectors will be in condition to be realized ; but its 

 beneficial effects in improving the drainage and ventilation 

 of the deep workings, and in reducing their temperature, 

 which have been very serious and expensive drawbacks 

 to the profitable exploitation of the Comstock Mines, are 

 said to be already very plainly manifest. It will no doubt 

 soon be settled in what way it can be made most useful, 

 and whether the advantages gained by draining, ventilat- 

 ing, and cooling the deep workings will or will not be se- 

 riously impaired by choking it with trains of cars, as it is 

 thought will be the case, if the ores are to be taken through 

 the tunnel to be concentrated and reduced at Carson, where 

 the mouth of the tunnel is located, and to which place the 

 Tunnel Company contemplate the removal of most of the 

 mining and milling operations now carried on at Virginia 

 City. Under any circumstances, however, the value of the 

 tunnel is conceded on all hands; and the editor of the Engi- 

 neering and Mining Journal even affirms that " there can 

 be no doubt, that in one way or another, it will be the sal- 

 vation of the deep workings on the Comstock lode." < 



