254 
PROCEEDINGS OP THE VICTORIA INSTITUTE. 
Tynemouth . — An example of a Harbour of Refuge for 
mercantile shipping is that at the mouth of the River Tyne- 
^rhere piers have been constructed on each side of the river, 
f converging towards each other, and having an entrance 
1,300 feet wide, with a depth of about 30 feet at Low Water 
Spring Tides. These piers are respectively some 3,000 and 5,000 
feet long, and were commenced in 1856 and completed in 1896. 
(3) Tynemouth. 
of concrete Twt 3 SU °unf tk °'l e men tioned are usually constructe 
is levelled off In ? re , tke foundation is of rock, this roc. 
spot where n ^f VerS ’ ^ ^ drilled “ the rock at an; 
explosive placed th t* 7 - a ° d °^ ar g®s of dynamite or simila 
charges are not t nn i,' P111 a , nd fi pe d ; care being taken that th 
to found work £57’ T the r( , ,Ck U P° n - hich it is in tender 
is the formation of th? I ^ ea ^ , C . racked - The next proces: 
blocks is to be placed. For thfc,°fh Whlch the , lowest course oi 
being to deposit one or m °> P 1 18 t * lere are various methods, one 
tp erect a wood-woi k f r ™ a T ers bags of concrete ; another 
and having b 7 bolts let into the rock 
and then filling this framewn t >' adjusted to the required level 
method is to make U p th e T°?„J ,tk COncrete in mass. A third 
layer of broken stone similarTo rrf ° f tke TOcfc surface by a 
escaping sideways by sealing f ho vr^ m . eta, i> preventing it from 
The two first-mentioned methods^w^b^h 8 ™ 8,11 bag8of D conC ^ 
- e both m use at Peterhead 
