Polytechnic Association. 599 



terrific scale, the operation of one of the simplest and best known 

 chemical laws in the rapid combination of the oxygen of common air 

 with combustibles already heated to the point of ignition. 



In this enlightened age we do not connect the disasters resulting 

 from the operation of natural laws with the sins of those who have 

 suffered by such disaster, yet every injury which arises from a disre- 

 gard of the immutable laws appertaining to matter should be received 

 as a Divine admonition ; and in the sad case alluded to, the lesson 

 taught us is, that combustible materials cannot be used with safety in 

 the construction of compact rows of dwellings, shops and warehouses. 

 If buildings are brought into close proximity, safety from' general con- 

 flagration can only be insured by the use of materials in their con- 

 struction which are absolutely fire-proof. The discussion of this 

 important cpiestion will doubtless be renewed in this Society. In the 

 meantime let us remember that, although a violation of physical laws 

 often involves us in evils, the laws are the dictates of infinite wisdom, 

 and that obedience to them has rapidly developed the material great- 

 ness of our race. 



The Chairman then introduced Prof. James A. Whitney, who had 

 recently visited California, and who read a paper entitled 



A Day at the Comstock Lode. • 

 By Prop. James A. Whitney. 



The Comstock Lode, over which are built the permanent mining 

 camps of Virginia City and Gold Hill, was discovered about twelve 

 years ago. Since then, it has yielded more than $120,000,000 in silver 

 bars, and the shafts sunk in it are among the deepest on the continent. 

 Its out-crop is in one of the many mountain defiles in the barren por- 

 tions of Nevada, and twenty-one miles south of Reno, on the Pacific 

 railway, from which it is reached by stage. The coaches start from 

 Reno at one o'clock in the morning, and reach Virginia City about 

 five. Returning, they leave Virginia City at half after seven in the 

 evening, and reach Reno in time to connect with the train bound 

 west. This, a few weeks since, enabled me to turn aside from my 

 direct route for twenty-four hours to visit the famous silver deposits, 

 and the trip gave me as much of interest and information as one could 

 well compress within the experience of a single day. \ 



Several stages start from Reno nearly simultaneously, keeping about 

 a quarter of a mile apart to avoid each other's dust. They are com- 

 monly crowded ; three seats, with three passengers to a seat, and half 

 a dozen more on top. Taking an inside place,- 1 soon found the coach 



