786 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 



aerated by the artificial tidal motion, which is the most essential feat- 

 ure of this arrangement, rising and falling through the cheese-cloth 

 and the complementary supply of air having ingress and egress through 

 a hole bored in the upturned bottom of the jar. It is supposed that 

 the ingress of water from the bottom disturbs the eggs enough to change 

 their position and gives each egg its share of the water-supply ; but 

 it is questionable whether the arrangement secures sufficient change of 

 water throughout the mass of eggs to maintain them in a condition of 

 healthy and normal development. As yet there has been no oppor- 

 tunity of comparing the artificially hatched fry with those hatched in 

 the natural waj r in the open sea. 



A very important improvement has been effected in the water service 

 during the past season. Two circular tanks with an aggregate net capac- 

 ity of 17,000 gallons, have been erected alongside the coal-shed, and are 

 served with a system of piping of which the mains are formed of log 

 pipe wound with iron and covered with coal-tar, and the smaller pipes 

 of hard rubber. We are consequently now entirely free from the diffi- 

 culties that used to arise from the presence of iron rust in the pipes and 

 hatching apparatus and which was, in fact, a very serious difficulty. 

 The new system was put in operation on the 7th of December, and, 

 with the exception of an occasional muddiness, resulting from heavy 

 rainfall, the water has been admirably pure ever since. 



The number of hatching boxes brought into operation during the 

 winter was 21. They were arranged in series of three boxes each, and 

 the amount of water fed to each series amounted to 150 gallons per 

 hour, or a total of 1,200 gallons per hour. The total net capacity of 

 the tanks is 17,000 gallons, so that in case of a suspension of pumping 

 the hatchery can be made to run about fourteen hours without any cur- 

 tailment of the quantity before the supply would be exhausted. 



The Chester hatching boxes appear to be well adapted to the purpose 

 of hatching buoyant eggs, yet, like most other new inventions, to be 

 capable of simplification. A few boxes on essentially the same plan, 

 but with simplified details, were constructed and found to work quite as 

 well as those built on the original design. With the ordinary water- 

 supply, which was about 150 gallons per minute, the period of each 

 tidal pulsation was about ten minutes. The automatic action of the 

 apparatus is well-nigh perfect, interference of the attendant being 

 rarely necessary. It was, however, not considered prudent to leave the 

 boxes without attention during the night, and the night watchman 

 made regular examinations. 



Observations on the temperature and density of the water in the 

 hatchery were made daily through the months of December, January, 

 February, and March. From these it appears that the density was 

 very uniform, ranging from 1.0250 to 1.0200, and that the temperature 

 of the water ranged from 49° to 32°, the mean for the month,- 



being 38.7°. 



