20 



The present season there are about 900 jars filled in this 

 house, the take of eggs in Detroit River in November last 

 not being sufficient to till the jars. However, with the 

 average hatcli, the house will turn out about 121,566,000 

 white-fish fry, to be planted in April and May, 1890, in 

 Michigan waters. 



The Detroit hatching-house, as constructed and equipped 

 in 1883, cost about $6,500 ; its subsequent improvement 

 and alteration, with increased apparatus, about $4,000 

 more. How such an establishment is stocked with eggs, 

 as it requires nearly one hundred solid bushels, and how 

 its millions of product are planted, it will take another 

 article to tell. 



ON THE DESIRABILITY OF THE ESTABLISHMENT, 



OF GREAT PUBLIC AQUARIA IN THE 



UNITED STATES. 



By William P. Seal. 



The beginning of the development of great public aquaria 

 in the United States will undoubtedly be hailed by anglers, 

 fish-culturists, biologists, and as well by the general public, 

 as a " consummation devoutly to be wished. ' ' Some past 

 experiences in this direction offer but little encouragenlent 

 if not positive discouragement, in this direction. But, as 

 in all advances in human knowledge, there is an experi- 

 mental stage of development by which, through repeated 

 failure, tliere comes finally a general knowledge of the 

 conditions required for success. In the case of fishes, 

 living in another element, the difficulties in providing 

 them with suitable conditions are apparently greater than 

 with land animals. There is the necessity of providing for 

 fishes in an artificial condition an abundance of oxygen, or 

 air, the amount of which, in suspension in water, from 

 various causes, is exceedingly variable, therefore requiring 

 an artificial system of aeration. 



