190 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



perature units required for incubation. It will be noted that although 

 the period of incubation varied from 48 to 90 days, yet the greater 

 number of eggs hatched at very close to 900 1. u. The failure of a few 

 lots to obey the general rule in most cases seemed to be due to some 

 special cause, such as a sudden fall in temperature when near the 

 hatching stage ; for example, those hatching on January 8 and 13. Fry 

 had already begun to appear at the top of the baskets before January 

 1, when a heavy snowstorm caused a drop of 5° in the temperature of 

 the water and delayed hatching for several days. A sudden rise in 

 temperature at hatching time also unduly accelerates hatching; note 

 those hatched on February 19, 22, and 28; about this time abnormal 

 variations of temperature prevailed, reaching a maximum difference 

 between morning and noon of 19°. 



Record of eggs hatched at Baird, Cal.y 1898-99, 



When 

 taken. 



When 

 hatched 



Reading 

 on day 

 taken. 



Reading 



on day 



hatched 



Tem- 

 per- 

 ature 

 units. 



Days. 



When 

 taken. 



When 

 hatched 



Reading^ 

 on day 

 taken. 



Reading 



on day 



hatched 



Tem- 

 per- 

 ature 

 units. 



Days. 



1898. 



1898. 











1898. 



1899. 











Sept. 6 



Oct. 24 



499 



1407 



908 



48 



Nov. 17 



Feb. 14 



1740.5 



2645 



904 



89 



7 



25 



521.5 



1423.5 



902 



48 



18 



14 



1754 



2645 



891 



88 



8 



27 



544 



1454 



910 



49 



19 



15 



1767.5 



2659 



891 



88 



10 



30 



588 



1500.5 



912 



50 



20 



16 



1782.5 



2671 



888 



88 



11 



31 



609 



1516.5 



907 



50 



21 



18 



1795 



2696 



901 



89 



12 



Nov. 1 



629.5 



1533.5 



904 



50 



22 



18 



1805.5 



2696 



890 



88 



14 



5 



en 



1591.5 



920 



52 



24 



19 



1827.5 



2712.5 



885 



87 



16 



7 



712.5 



1622.5 



910 



52 



25 



19 



1838.5 



2712.5 



874 



86 



18 



11 



754 



1670.5 



916 



54 



26 



20 



1849 



2729.5 



880 



86 



22 



17 



838 



1740.5 



902 



56 



28 



22 



1869 



2755.5 



886 



86 





1899. 











29 



^ 



1881.5 



2755.5 



874 



85 



Oct. 20 



Jan. 8 



1339.5 



2272.5 



933 



80 



30 



24 



1896.5 



2787 



890 



8(i 



23 



13 



1389 



2315 



926 



82 



Dec. 1 



26 



1910.5 



2809.5 



899 



87 



27 



16 



1454 



2341.5 



887 



81 



2 



27 



1924.5 



2820.5 



896 



87 



29 



19 



1485.5 



2379.5 



894 



82 



3 



28 



1936.5 



2834 



897 



87 



30 



21 



1500.5 



2404.5 



904 



83 



4 



28 



1947.5 



2834 



886 



86 



31 



21 



1516.5 



2404.5 



888 



82 



5 



28 



1958 



2834 



876 



85 



Nov. 1 



24 



15:33.5 



2440.5 



907 



84 



6 



Mar. 3 



1969.5 



2882.5 



913 



87 



5 



28 



1591. 5 



2489.5 



898 



84 





3 



1980.5 



2882.5 



902 



86 



6 



29 



1607.5 



2503 



896 



84 



8 



5 



1991.5 



2911.5 



920 



87 



7 



30 



1622.5 



2516.5 



894 



84 



9 



5 



2001 



2911.5 



910 



86 



*4 



30 



1576.5 



2516.5 



940 



87 



10 



5 



2010 



2911.5 



901 



85 



8 



Feb. 4 



1636 



2567.5 



931 



88 



15 



7 



2049 



2943 



894 



82 



10 



5 



1659.5 



2570 



910 



87 



16 



8 



2a59.5 



2959. 5 



900 



82 



11 



6 



1670.5 



2573 



902 



87 



17 



10 



2069.5 



2983.5 



914 



83 



12 



9 



1682 



2593 



911 



89 



20 



11 



2106 



2992 



886 



81 



13 



11 



1693.5 



2612.5 



919 



90 



18 



12 



2060.5 



3008 



927 



84 



14 



12 



1705 



2623.5 



918 



90 



22 



13 



2129 



3021 



892 



81 



15 



12 



1716.5 



2623.5 



907 



89 



27 



17 



2176 



3076.5 



900 



80 



* Very few eggs in this basket. Hatching always seems slower with a single layer of eggs than 

 in full baskets; probably less animal heat. 



The main advantage of this system of recording ^gg development 

 lies in the fact that information is secured at a time when it is needed. 

 By this it is not intended that entire reliance should be placed upon 

 the record for determining the condition of the eggs. On the con- 

 trary, the chief dependence should always be placed on their appear- 

 ance, especially in determining how far along they are in the tender 

 stage and when they are well out of the same. The information 

 obtained from the record is corroborative of our work and enables it 

 to be checked up. For example, when selecting eggs for shipment a 



