51 



spring pond, already mentioned, and in tlie basin at its 

 top was placed both old and fresh cow ordure weekly. 

 In the first pool there was a division of the water, and 

 in one half horse dung was frequently put, both fresh 

 and stale, and in all the pools was a deposit of duck 

 dung of the previous 3'ear, well dissolved, and stocked 

 with all the forms of life which it was thought desirable 

 to cultivate. At different times water was taken from 

 each of the five places in this wa}^ : One gallon from 

 the surface by immersing the measure, one gallon 

 from the middle and one from the bottom b}' means of 

 tubes, and the contents filtered through No. 8 wire 

 cloth, cheese cloth, and then through the finest of mill 

 silk bolting cloth. The last would retain almost all 

 but the smaller diatoms, and they were caught in a 

 funnel of filtering paper below all the other strainers. 



This work, being done twice each month for the 

 five months including April and August, should give 

 a fair average of the amount of food in the pools dur- 

 ing the season in which the operations were conducted. 

 The following gives the amount of entomostracans 

 obtained, and excluding snails and the diatoms. In 

 other words, the amount of food available for trout fry 

 in their first season, such as they can see, seize, swal- 

 low, and assimilate. The pools contained about 150 

 cubic feet of water, or 1125 gallons, of which 15 gallons, 

 or .\, were strained on ten different days, at the ist and 

 15th of each month. 



Of the above-named food 2.25 grams were caught, 

 equaling .225 grams per da}-. This multiplied by 75 

 gives us 16.875 grams for the entire water per day, 

 and again multiplied by the 153 days gives a total of 

 2,581.875 grams in the whole season. Dividing this 

 by 24 gives us 107.578 oz., a trifle less than 6^ lbs. 

 avoirdupois. 



We must consider the fact that no fish were feed- 

 ing in these pools, and that the calculation is made as 



