252 
PROCEEDINGS OP THE VICTORIA INSTITUTE. 
possible to fix the position from objects on shore, and this was > 
only done by noting at what time and at what point any one of ^ 
the above-mentioned lines of anchored boats was passed. 
Tide-Gauge . — The range of tide is observed by means of 
tide-gauges of which the most accurate is one such as is in use 
here, which has a float in a tube to which the sea has access;, 
this float actuates a pencil which marks on paper the movements 
of the tide, the paper uncoiling from one cylinder, moved by 
clockwork, and coiling itself, when marked, on another. The 1st 
cylinder is marked with the hours and records the time by punc- 
tures on the edge of the paper, noon of each day being registered 
by a special mark. 
T Vaves and wind . — The direction and force of the waves 
being in all ordinary cases determined by that of the wind the 
observations for each go, so to speak, hand in hand. ' The usual 
method of ascertaining the prevalent winds and their force at any 
place is to take an observation at a fixed time every day, for as 
long a period as possible, of the direction and velocity of the 
wind at that time, noting also during the day any sudden changes 
that may occur. For very accurate records the anemograph is 
used, which registers upon a paper the direction and velocity 
of the wind in a manner somewhat similar to that of the tide- 
gauge mentioned above. 
The direction of waves is of course readily observed ; their 
height is ascertained, bylines of sights at known levels. An- 
other feature with regard to waves that must be noted is what is 
known as their “fetch,” i.e , the distance that waves may be 
driven by the wind before reaching the shore on which they 
break ; thus, when we say that at such a place there is a “fetch 1 
of so many miles we mean ordinarily the distance from that 
shore to the opposite shore. This affects both height and velocity. 
Design . — Having obtained all the information possible the 
design of the Harbour is proceeded with, site for work-yard 
selected, and preparatory work commenced. Taking first 
Harbours of Refuge; these are formed by the enclosure of an 
area of water, more or less deep as required, within protecting 
moles or breakwaters, leaving an opening by which vessels may 
enter. A Harbour of Refuge, as its name implies, must be in 
such a position that vessels may enter it for shelter under any 
conditions of wind and sea, and on a part of the coast that is 
much frequented by shipping and is without any natural place 
of safety into which vessels may run in bad weather. There are 
determined m - l "f 1 " ', harbours of refuge whose position is 
<lete.ni.ned mainly by strategical considerations, a refuge from 
