216 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
lish by calculatiou, based on the diameter, a standard for measuring eggs on trays; 
and the difficulty amounts to almost impossibility when it is attempted in like man- 
ner to determine the number of eggs in a given bulk. This at once becomes apparent 
by reference to the accompanying diagram. To determine the number of eggs on a 
tray, the general practice has been to count the number of eggs on two of its adjacent 
sides and multiply them together; it being assumed that the product was the number 
of eggs on the tray. This would be true if the eggs arranged themselves as shown in 
Fig. 2, Plate 36. As a matter of fact the eggs really group themselves in a different 
manner (see Fig. 1, Plate 36), nearly obliterating the void space between the eggs. 
Theoretically but sixty four eggs, one-eighth of an inch in diameter, will occupy 1 
square inch; practically we get over seventy-five. When we come in like manner 
to estimate eggs in bulk occupying a known cubic space, the error becomes greater 
by reason of the obliteration of the void. The eggs on the second layer do not occupy 
a position directly above those on the first layer ; that is to say, the nadir of an egg 
on the second layer does not coincide with the zenith of an egg on the first layer, but 
falls in the center of a void formed by three contiguous eggs. From this it follows that 
the altitude of two layers is less than two diameters of an egg. It is a legitimate 
conclusion that a bulk 1 inch deep of eggs one-eighth of an inch in diameter will 
have more than eight layers of eggs. It will require a higher knowledge of applied 
mathematics to solve^his problem than is generally possessed by fish-culturists. 
While employed at the Central Station of the U. S. Fish Commission, at Wash- 
ington, D. C., in charge of hatching, from 1882 to 1888, 1 devised a system of measur- 
ing fish eggs and fry. It is applicable to all classes of semi-buoyant and heavy eggs, 
and is, I believe, based upon rational principles. No one recognizes better than I that 
it still possesses inaccuracies, which only time, close observation, and determined 
practice can obliterate. The basis of this system is the number of eggs in a standard 
quart of the United States (57.75 cubic inches) determined by actual count of each 
egg. In the table here given some of the varieties of eggs were not obtainable for 
counting; these have been computed from their known diameter, due allowance being 
made from absorption of the voids. In all cases stated to be counted, the count has 
been made of each egg in the measure. 
