and Laboratory Methods. 



1405 



The Cone Net. 



This net was originally described in the Transactions of the Wisconsin 

 Academy of Sciences, Arts, and Letters, Volume VIII, page 397, 1892. Since 

 that time I have had numerous inquiries for directions for the construction of 

 the net, and in response to these I give the following account of the net as I 

 now use it. The apparatus is still very crude and improvements can easily be 

 suggested. It has met my purposes, however, and therefore for some years I 

 have given no attention to improving its details of construction. The metal 

 parts of the apparatus are illustrated in the annexed figures. The diameter of 

 the base of the cone top in the net which I now use is three inches. From this 

 the scale of the drawings can easily be computed. The cone top is represented 



in Fig. 1. It consists of a rim of stout tin (A) three inches in diameter, one 

 inch in height, with a stout wire turned into the lower edge. To the inside of 

 this is soldered a wire loop (B), which lies under the cone and projects through 

 its apex in a loop to which the line is attached. The top of the net is formed 

 by a cone of brass wire netting (C), one-twentieth of an inch mesh, with a slant 

 height of four inches soldered to the rim and to the wire loop at the top. The 

 bottom of the net (Fig. 3) is formed by the screw top of a kerosene can, to 

 which is soldered a cylinder of tin about one inch in height and one and one- 

 fourth inch in inside diameter, into whose upper edge a stout wire is turned. 

 The dredge net is fastened to these two metal parts, being firmly tied both at 

 top and bottom. The tying must be firm, or if the net is thrown when contain- 

 ing water it may be pulled off from the cone top. I have found it a good 

 method of tying to use a dry string drawn tightly, of a kind which will shrink 

 when wet, and to tie the net twice, turning the edge down over the string of the 

 first tying before fastening it the second time. For a net I use a fine cotton 



