204 : GLAUCUS; OR, 
Next, you must make up for evaporation by fresh 
water (a very little will suffice), as often as in sum- 
mer you find the water in your vase sink below its 
original level, and prevent the water from getting 
too salt. For the salts, remember, do not evaporate 
with the water; and if you left the vase in the sun 
for a few weeks, it would become a mere brine-pan. 
But how will you move your treasures up to town? 
The simplest plan which I have found successful 
is an earthen jar. You may buy them with a cover 
which screws on with two iron clasps. If you do 
not find such, a piece of oilskin tied over the mouth 
is enough. But do not fill the jar full of water; 
leave about a quarter of the contents in empty air, 
which the water may absorb, and so keep itself fresh. 
And any pieces of stone, or oysters, which you send 
up, hang by a string from the mouth, that they may 
not hurt tender animals by rolling about the bottom. 
With these simple precautions, anything which you 
are likely to find will well endure forty-eight hours 
of travel. 
What if the water fails, after all ? 
