148 THE ROYAL SOCIETY OF CANADA 



that a suitable technique had to be developed as the tests proceeded, 

 and occasionally unexpected results occurred. In the winter of 1917 

 three sedimentation markers were set out. Holes were cut in the 

 ice early in January. The total thickness of ice was over two feet, 

 but this was covered by six inches of water, the result of a January 

 thaw. Through the hole enamelled (agate) pails eight inches in 

 diameter with straight sides were lowered. The handles had been 

 removed and two straight pieces of wire at right angles to each other 

 were fastened to the top of each pail. A float of varnished pine was 

 attached by a copper line to the wires at this part of intersection. 

 This pine float was of a size to support amply the weight of the wire, 

 but could not support the weight of the pail in the water. The depth 

 was first ascertained and the copper wire cut off so that its length was 

 about three feet shorter than the depth of the water at each station. 

 In this way the whole was lowered gently into the water so as to avoid 

 disturbing the bottom, with the float drawn down about three feet 

 below the surface of the water. The holes were then filled up with 

 snow which rapidly froze in the water. All this precaution had to 

 be taken to avoid the advances of curious and inquiring outsiders. 

 It was, of course, absolutely essential that the markers should not be 

 disturbed. Their position was determined by compass intersections 

 from prominent points as well as by distances measured by a telemeter. 

 The wire was suspended in the above manner to avoid the possibility 

 of the thin film of sediment being washed out as the pail was drawn 

 to the surface. When the latter was about to be lifted, the wire was 

 passed through an opening in the centre of a tin cover of slightly 

 greater diameter than that of the pail. On being gently lowered by 

 means of a string, the cover fitted exactly over the top of the pail. 

 This avoided the disturbance or loss of any material in the pail as 

 the latter was drawn to the surface. 



This unfortunately yielded entirely negative results. When the 

 pails had been down three months they were examined but found to 

 contain no appreciable sediment. A second inspection after the ice 

 had gone showed that they had been removed and later two of the 

 floats were discovered along the shore. 



The following winter, 1917-18, pans of the same nature as the 

 above were set out in the same places but with a different method of 

 attachment. Before the ice was set in the fall, the pans were lowered 

 and connected to shore by woven cotton rope. Small weights were 

 attached to hold the line to the bottom, and to avoid pulling over the 

 pail as the line was led to near shore. The end was left lying in the 

 water at a recognizable spot. The day following the ice had com- 



