562 BULLETIN OF THE BUREAU OF FISHERIES. 
the ring under repeated flexure when rigidly attached. In the latter case the 
insulation was abraded by the rubbing of the rough edges of the broken lead 
casing, and the exposed core broke by the concentration of flexure at the 
weakened point, or else, coming into contact with the lead, was destroyed by 
electrolysis. ’ 
To overcome this, horseshoe-shaped porcelain pieces were interposed 
between the rings and the wires, as shown in figures 1 and 2. By this means 
the electrically antagonistic metals were kept apart and at the same time there 
Fic. 2. 
Fic. 1 AND 2.—Showing insulated attachment for lead-covered lines supporting sponge cuttings. 
was formed a rocking attachment without wear on the lead, the flexure of the 
wire being distributed throughout its length instead of being concentrated near 
the stakes. 
With galvanized iron wire with underwriters’ insulation and incased in lead, 
this device served very well so long as the sponges were not much over 4 inches 
in diameter, but when they grew larger there was a contingency which had not 
been anticipated, the sponges being torn loose and rotating on the wire. Practi- 
cally all of the wires used were less than one-fourth inch in diameter, a larger 
size being objectionable on account of its weight and the hole produced in the 
