144 ROYAL SOCIETY OF CANADA 



of its adhesive nature it may be mentioned that it sometimes grows upon 

 the outer face of a waterfall over which large rocks are carried by the 

 swift running water. Anchor ice forms upon the rocks when the sun is 

 not shining and in this respect, as well as in appearance, it is like frazil. 

 When the sun's rays impart a minute amount of heat to water under 

 which anchor ice has grown the latter loosens its grip upon the bottom 

 and rises to the surface. It then floats, as a mass of snow would do, 

 almost entirely submerged, but with no trace of the inclination which it 

 possesses at the bottom to cling to other objects. In this condition, if 

 the masses are broken up, it will readily pass through hydraulic power 

 plants with the w^ater which operates the latter. 



Frazil which is really the bugbear of water power plants is formed 

 in an entirely different manner. Frazil forms upon the surface of water 

 and it would be unknown if the surfaces of canals, streams and lakes re- 

 mained smootli w^hen winter was setting in. When these surfaces are 

 disturbed, however, by the wind, or by the current, or in rapids, the icy 

 spicules, into which the tops of the waves and the spray of water are 

 turned, are prevented from uniting together and forming a sheet of ice. 

 These spicules are known as frazil. Frazil forms most abundantly in 

 open rapids which never have a protective covering of sheet ice, but it 

 also forms upon the surface of any body of water — such as a lake or a 

 canal — if the water's surface is disturbed by any cause which retards or 

 prevents sheet-ice from forming. As Canadian winters are usually borne 

 in upon the wings of a cold northwest wind, which roughen the surface 

 of the waters, it is not uncommon to see hydraulic plants shut down by 

 frazil, although situated at a supposedly immune-from-frazil location. 

 Two notable examples in line with this contention may be cited : One of 

 these is at the hydro-electric power plants, at Deschenes, Quebec, — just 

 across the river from Ottawa's summer resort, Britannia Bay, — and, the 

 other is at the Water Works Pump House of the City of ]\lontreal. 

 Frazil has often shut down both of these works. One has a stretch of 25 

 miles of smooth lake and river above it, and the other has many miles of 

 quiet canal for a head race. The terms " smooth lake " and " quiet 

 canal " are only applicable to these, or any other bodies of water, when 

 the wind is not blowing. 



Frazil, then, is likely to form upon tlie surface of any body of water 

 when the latter is not protected from the action of tlie cold air by a layer 

 of sheet or surface ice, or by some artificial covering. After surface ice 

 is once formed frazil is made in open rapids only, and it does not 

 then enter power plants because it clings to the surface ice under which 

 it mav be carried bv the current. If the surface ice is removed bv a 



