EVAPORATED SEA WATER. 358 



had for sixpence. This may always be kept in the 

 tank. When ' all's well ' it sinks to the bottom, 

 and when anything comes amiss it rises to the sur- 

 face, but falls again quickly upon the introduction of 

 the fresh water. 1 



A more simple plan is, to mark on the glass the 

 height of the fluid when the tank is first filled, then 

 as the water sinks, raise it again to its original level 

 by means of fresh water. 



Many persons decline starting an aquarium on 

 account of the great difficulty of procuring a proper 

 supply of sea-water. This objection, of course, can 

 be offered only by those who happen to reside 

 inland ; but even these need not now be dis- 

 couraged, for an ingenious plan has lately been de- 

 vised for sending the commodity in question through 

 the post ! 



Mr. Bolton, chemist, Holborn Bars, London, sup- 

 plies, not sea- water, but ' marine salts for the in- 

 stantaneous production of sea-water/ About six 

 ounces is sufficient to make a gallon, by the applica- 

 tion of fresh water. The saline material here 

 alluded to, is not an artificial chemical compound, 

 but is produced by the simple process of evaporating 

 sea- water itself. Those individuals so fortunate as 

 to possess a marine villa, or any other more humble 

 residence at or near the sea-coast, have no occasion 



1 Vide author's " Sea-side and Aquarium." 



