INDUSTRIAL PROGRESS DURING THE YEAR 1873. cxxi 



feet, or four and three-quarter miles. It is twenty-six feet in 

 wiclti], and varies in height from twenty-three to twenty-six 

 feet wherever a brick arch is used. Passing through solid rock 

 excavation, the section is reduced to twenty-four feet wide by 

 twenty feet high. Another engineering enterprise of some 

 magnitude, the Cleveland Water-works Tunnel, which has 

 had a history almost as checkered as the enterprise above al- 

 luded to, has likewise been completed during the year. The 

 capacity of the tunnel is from sixty to seventy million gallons 

 of w^ater daily : amply sufficient to supply the city when it 

 shall have a population of a million, should that time ever 

 arrive. 



The completion of the Underground Railways through the 

 city of Baltimore during the past year is worthy of record, not 

 so much on account of the novelty or magnitude of the un- 

 dertaking, as because this is the first systematic movement 

 in the country to inaugurate the underground-railway sys- 

 tem, which has been long since adopted very extensively 

 abroad, as the most rational solution of the problem of rail- 

 way transit through populous cities. 



The tunnels in question form two distinct lines, whereby 

 nearly all the railroads centring in the city have been 

 brought into connection, greatly adding to public conven- 

 ience and facilitating business intercourse. Their total length 

 is three and one-half miles, of which about two miles are 

 closed tunnels, and the remainder open cuts, over which the 

 streets are carried on brido'es. 



The work upon the great steel bridge at St. Louis is not 

 completed, but is being pushed steadily forward, as is also 

 the work upon the tunnel connecting with it. 



Of engineering enterprises which have been projected, per- 

 haps the most interesting is the proposal to pierce the Rocky 

 Mountains with a tunnel. The objects and advantages to be 

 gained therefrom are stated to be the development of new 

 mineral veins, and of the resources of that region of country, 

 by increasing the facilities of transportation. If ever com- 

 pleted, it will be carried through from a point near Black 

 Hawk, and will come out in the Middle Park. The tunnel 

 will be twelve miles long. It is declared that work from the 

 Middle Park will be commenced early next year, and that 

 already much of the preliminary preparation has been made. 



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