436 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [10] 



be considered as a large percentage. If, in order to test the matter, we 

 suppose that there is enough liquid between the globes of the eggs, to 

 allow them to fill the space, without pressing against each other, it 

 follows that every egg having a radius = 1 must lie in a dodecahedron, 

 whose half height h would be =;= 1.6343, whose basis at the plane of this 

 naif would be 5.1955 square meters {g), whose hollow space would there- 

 fore, be — 



Xr=Vfe\ gg^g cub. 



whilst the globe r would be =1=4.186 cub. 



so that the quantity of liquid in the mass of eggs would be=1.489 cub. 



This would be 26.21 per cent, liquid. As the eggs actually pressed 

 against each other, and as no liquid gathers on the top of them, the 

 percentage of liquid must be less that 26.21; and the actual quantity of 

 liquid would be betf^een 14 and 20 per cent., but it is certain that the 

 percentage of liquid varies greatly. The liquid acts as a strong alkaline 

 reagent, and contains an albuminous substance, which can be obtained 

 by boiling and by acetic acid, and which, when precipitated by alcohol, 

 cannot be dissolved again. 



Eggs which had not been impregnated, when thrown in salt water, 

 float near the surface, the specific gravity being 1.0156 and the temper- 

 ature 5.3° C, and the specific gravity being 1.0141, the temperature 

 17.5°, and the saltness 1.85 per cent. ; they begin to sink at a specific 

 gravity of 1.0146 and 5.3° 0. = 1.0131 specific gravity at 17.5° = 1.72 per 

 cent, saltness. Of the impregnated eggs one-half float near the surface 

 at a specific gravity of 1.0155, at 7.04o C. = 1.0145 at 17.5° C. = 1.90 per 

 cent, saltness. Probably, however, these eggs were still covered with 

 spawn to a considerable extent, for in the open sea the^^ floated near 

 the surface at a less specific gravity. When the eggs are impregnated 

 in a thin solution of salt, and are then examined as to their capacity for 

 floating, they do not appear noticeably lighter than when they are im- 

 mediately thrown in a concentrated solution. At least the difference 

 is very small. 



As in liquid the eggs have a specific gravity of at least 1.0161 at 8.7° 

 C, but in salt water of 1.0155 at 7.4° C, it seems that in the latter they 

 absorb some of the water which does not contain much salt. For prac- 

 tical purposes, however, it is suflQcient to know that in order to keep 

 the eggs afloat near the surface, the percentage of salt in the water 

 should not be less than 1.85 per cent., and should at any rate be higher 

 than 1.72 per cent. The weight of the eggs is not entirely the same. I 

 have not yet examined eggs which had developed more, as to their 

 weight, which probably had changed somewhat. Cod eggs freshly laid 

 in the water would, at a specific gravity of 1.015, weigh from 1.5 to 1.7 

 milligrams. 



In a similar manner the eggs of the plaice (Goldbutte) were deter- 

 mined. For this purpose I selected four fish having an average weight- 



