MECHANICS AND USEFUL ARTS. 49 



Boston to East Boston. The tunnel would be sunk below the 

 bed of the channel, and the weight of its solid masonry would be 

 Buch as to overcome any tendency to rise from hydrostatic pres- 

 Bure, if by chance a film of water, communicating with the super- 

 incumbent water, should gain access to the under surface of the 

 tunnel. 



HOOSAC TUNNEL. 



The Joint Standing Committee of the Legislature of 1867, upon 

 the Hoosac Tunnel, have made a report to the Legislature in re- 

 gard to the progress made in the work during the last year. 



The total progress made on the east-end heading during the 

 year was 1,187 feet, — more than double the advance made in 1866, 

 and giving an average of 118.17 feet per month during the last 

 half of the year. The sides of the tunnel have been enlarged to 

 the full width during the past year, a distance of 2,400 feet from 

 the portal. 



The total number of men employed upon the tunnel on the 1st 

 of January last was 509, and the amount expended on the tunnel 

 from November 1, 1866, to January 1, 1868, was $603,666. The 

 total cost of the tunnel up to the commencement of the present 

 year has been $2,086,640. 



The distance accomplished in the east heading in November 

 was 126 feet ; in December, 101 feet ; in January work was sus- 

 pended owing to the accumulation of anchor ice ; in February, 

 131 feet; March, 112 feet; average cost per cubic yard, $9,14. 

 Thirteen hundred feet of the east end has been enlarged since 

 November, at an average cost of $5.98 per cubic yard. 



The following figures show what had been accomplished in the 

 entire work to April 1st, and also what remains to be done to com- 

 plete the tunnel: East-End Heading, 4,951 feet; West Shaft, 

 East Heading, 1,396 feet; West Shaft, West Heading, 692 feet; 

 West End, 659 feet; West-End Arch, 612 feet; Well No 4, 207 

 feet ; Depth of Central Shaft, 583 feet. 



Distance yet to go : From East-End Heading to Central Shaft, 

 7,886 feet; from Central Shaft to East Heading, West Shaft, 8,351 

 feet ; from West Heading, West Shaft, to Well No. 4, 232 feet ; 

 from Well No. 4 to West-End Heading, 864 feet ; from bottom of 

 Well No. 4 to Grade, 8 feet ; from bottom of Central Shaft to 

 Grade, 447 feet. 



TUNNEL UNDER THE TEES. 



The following is a plan of Mr. Head, of England, for tunnelling 

 the River Tees from Middlesboro' to Norton Junction. 



"I propose that it should be a single wrought-iron tube, but 

 divided into two passages by a water-tight web or bulkhead. 

 This division should be strong enough to resist tlie pressure of the 

 water, and preserve, at least, one side for traffic in case of acci- 

 dent to the other. 



** As to the construction of the main tube, I would recommend 



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