SCIENTIFIC SUMMARY. 
431 
wards liis lifeless body rose to the surface. On the following day he was 
buried in Half-tree Churchyard, Kingston. Thus sadly, at the age of 
twenty-five, ended as brave a life and as noble a spirit as science has ever 
fostered. 
In a letter to the writer, Professor Sedgwick speaks of having felt for 
him “sentiments almost of paternal love;” and goes on to say, “ Natural 
science has been deprived of the services of one whose genius, and zeal, 
and intrepidity gave a promise of a glorious harvest of honour to himself, 
and, I might say, to his country.” 
MECHANICAL SCIENCE. 
The Repair of the Great Eastern . — It will be remembered that this vessel 
struck on a sunken rock at the entrance to Long Island Sound in August 
last, ripping open the outer skin of iron plate for a distance of 85 feet, the 
fracture measuring in width as much as 4 feet at parts. Owing to her 
peculiar construction with a double sheathing, the interval between the 
skins being divided into cells, she was enabled, notwithstanding the 
accident, to proceed on her voyage and land her passengers and cargo in 
safety. It is even thought that she might have returned to England 
without danger. The agents of the Company in New York, however, 
determined on her repair before risking another voyage, and there being 
no dock of sufficient size, a novel and ingenious plan was resorted to, 
for gaining free access to the damaged part. A timber caisson, coffer, or 
“scow,” was constructed, 104 ft. long, 15 ft. wide, and 8 ft. high, of 
great strength, and fitting, as closely as might be, to the curved side of 
the vessel. This was sunk over the fracture, and sustained in its place 
by chains passed round the hull. A water-tight joint between the 
“ scow” and the side of the vessel was constructed by means of an 
india-rubber hose-pipe, placed in a shallow groove round the edge of the 
“ scow,” and when the latter had been firmly fixed in its place, filled 
with water under pressure by a force-pump. The “ scow” was then 
pumped dry and formed a long water-tight chamber on the outside of 
the vessel, to which access was gained both for men and materials by 
two trunks, each 6 feet square, curving upwards along the side of the 
vessel to a point above the water level. A patch from 4 to 6 feet wide, and 
93 feet long, was then riveted over the fracture, and the vessel rendered 
as strong and seaworthy as before the accident. The vessel is now under- 
going repair on the shores at Rock Ferry, near Liverpool; and was for 
several days high and dry on the beach, so that spectators could walk 
round and examine every part of the hull. 
The Metropolitan Railway . — The opening of this subterranean line 
marks a successful step towards the relief of the overcrowding of metro- 
politan thoroughfares. The depth from the surface to the level of the 
rails varies from 26 to 54 feet at different parts. The tunnel is elliptical, 
17 feet high and 28-| feet span, except in the deeper portions, where the 
height of the tunnel is increased. The gradients do not exceed 1 in 
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