BIDWKLL — HARBOUR WORKS. 
2,57 
there are 157 acres of wharf space and standage ground, with 
wrehouses for grain, Esparto grass and general merchandize. 
The gates are opened and closed, and many of the quay cranes, 
and all the hoisting machinery in the warehouse worked, by 
hydraulic power. There are of course several miles of railway 
sidings on the wharves and standage ground, and these connect 
with a main line, and with several local colliery lines. There 
are two other docks upon the River Tyne, but I have chosen 
this one to give a few particulars of, as it is the last constructed. 
Quay and river walls if constructed in the water are, as I have 
said, carried on much on the lines, previously described, of sea- 
works. I may mention that a portion of the river quay wall at 
the Albert Edward Dock was constructed by means of twin 
barges, bearing a bridge-crane from which was hung, between 
the barges, the block to be set. 
The making of quays and whavves may consist in building 
the quay wall in the water as above and afterwards reclaiming 
the land behind it by means of filling in, or of building it behind 
land which is afterwards to be removed. The actual quay is 
sometimes constructed of timber, but in this case it is a ways 
done, at any rate the front portion of it, in the water ; the law-i) 
tf any, necessary to be removed, having previously been dte ge 
awa y. And this brings me to dredging. There are various 
types of dredgers ; hopper-dredgers, which load themselves ana 
carry away their spoil to sea ; barge-loading dredgers with single 
double chains of buckets; suction dredgers, which act witti 
a powerful pump; and single-bucket and grab-dredgers. 
these the most common type is the barge-loading re » ’ . 
as we have here at Port-of- Spain, and on works w ler 
ttnich dredging to be done there will be several o iese. 
Where the material to be removed is ^artb clay sand or 
aud, the dredging proceeds without any prevmus operatK n but 
w here rock is to be dealt with it is first broken up 1 oy blasU ng 
with dynamite or kindred explosives, and a c ° , certain 
doing this is to place several charges upon the bottom at c^tam 
distances from each other and firing them, 
rock, forming a number of basins, as i ’ crac ked and 
other and with the portion between each ab» up the 
shaken ; the dredger then goes over e S r , t q ic required 
shattered material. This process is rep , owu ^ « patch- 
depth is reached. This system of blasting ; i „ charges of 
blasting,” and I have seen it used wit i 8* ' , circular 
»» io is P =»d, of Ld * 
excavations in the rock of some - dredger and also a 
deep. There is a form of single-bucket dred s er 
