COLORADO MINES. 301 



*two be SO different, though both may be made from the same stock, that the 

 strength of the larger cannot be inferred, but only guessed at, from' the known 

 strength of the smaller. In the larger there is more likely to be permanent op- 

 posing strains that destroy a large percentage of its strength. A remarkable in- 

 stance of opposing strains, caused by treatment in manufacture, was pointed out 

 some time ago by Colonel Paine. He found that wire coiled before it was set 

 could not be even straightened without straining the sides beyond the limits of 

 elasticity, and that such wire had nothing near the strength of that coiled straight. 

 As the strength of a large metallic member of a structure cannot be tested by any 

 machine within the reach of individual means, and as to obtain the best results 

 requires the combined skill of several classes of experts, the aid of Congress is in- 

 voked to provide a suitable machine, and to create a board of experts whose va- 

 ried skill shall plan the best experiments. 



Undoubtedly the progress of the age, which is so largely engineering prog- 

 ress, does on the whole greatly increase the welfare of mankind. By making 

 the forces of nature do the hard work, the labors of the toiling milUons are light- 

 ened many fold. The laboring man now works with brain and eye more than 

 with muscle, and his business is now to apply some principle of science. This 

 raises him intellectually. He now has time for improvement. Comfort and re- 

 finement, and even luxury, are brought within his reach. The forces of nature 

 having become obedient to the will of man, they are made to produce for him 

 not only plenty, but conveniences and luxuries formerly undreamt of. By the 

 present facilities the races of men are brought into contact with each other. 

 Those races are being assimilated, and the prejudices and hatreds of the past are 

 fading away. Supreme power among men is more than ever in the hands of the 

 most enlightened, and they are sending civiHzation and Christianity into the re- 

 gions most benighted. The light of Heaven is beginning to shine into the Harem 

 and the Zenana. And the time seems to be hastening when there shall universally 

 prevail "peace on earth " and "good will toward man."— f^;z Nosirand' s Mag- 

 azine. 



COLORADO MINES. 



Leadville Smelters. — The production of the Leadville smelters, during 

 the month of July, shows 3,604 tons of base bullion, which, after deducting for 

 <iross and the precious metals contained in the same, would leave at least 3,500 

 tons of lead. Every month so far this year has shown a gain over the corre- 

 sponding period of last year. During the fore part of the year, one month showed 

 a product of 4,000 tons, the output of the Leadville reduction- works. There is 

 now very little question but that the product for the year will aggregate between 

 40,000 and 43,000 tons. The shipments of lead during the first six months 

 amounted to 21,898 tons, and up to date to 25,500 tons. There have also been 



