SEAWEED GATHERING. 
123 
supply of the useful rays, or shield it, as is much more likely, 
against the excess of the blue rays, has not been determined by 
experiment. 
If seaweeds cannot grow on the floor of the deep sea, they 
yet inhabit “ blue water.” I am not specially alluding to forms 
like the gulf-weed of the Sargasso Sea, but to the enormous 
abundance of microscopic Algas floating in the surface layers 
of all seas. They occur in inconceivable abundance everywhere, 
from the polar seas to the equator, and form the food of minute 
animals, which in turn support the fishes. They are fewer in 
the number of species than the shore Algae, but immeasurably 
greater in numbers of individuals and in the mass. The mere 
fringe of seaweeds round our coasts Oould never support the 
animal life of the sea by itself, and this floating microscopic 
vegetation is the pasture ground of the animals of the ocean. 
It will give you some idea of its extent if we make the following 
comparison. The Sargasso Sea is, compared with other tracts 
of the ocean, poor in this minute vegetation, but if we were to 
collect the whole of it in fine silk tow-nets, and make a great heap 
of it, and make another heap of all the big gulf-weeds in the 
same sea, the mass of the individually microscopic forms would 
greatly exceed the other. They are very little known as yet, 
these microscopic pelagic Algae. In the cold seas especially 
they are principally diatoms with siliceous membranes, and in 
the temperate and tropical seas great numbers of others called 
coccospheres and rhabdospheres, occur with incrustations of 
carbonate of lime. When they die, these hard mineral parts 
sink slowly down on the bottom of the deep sea, and form a 
deposit of much geological interest. 
But we have been long enough in the deep sea, and must 
begin to think of what we are to do with the specimens you have 
been collecting, white absorbing all this dry information. No 
need to give directions for drying the specimens. The floating 
of them out on mount papers, the placing a layer of muslin over 
them to keep them from sticking to the drying paper, are really 
the only points of difference from drying land plants. Then the 
process of pickling them in spirit after treatment with picric 
acid is one that appeals to the special student, and is already 
well enough understood by him. To keep them alive in aquaria 
for observation is perhaps more to the taste of the Selbornian. 
This is an extremely difficult matter with all but a few forms. 
Those from deep water are beyond all ordinary appliances and 
precautions, being very easily injured by light and the least rise 
of temperature. In all cases keep very few specimens, and these 
small ones, if you mean to succeed. Never expose them to 
direct sunlight, but let the room be well shaded and the cooler 
the better. A cellar with very little light is the best place. You 
will certainly kill them by aerating the water more than a very 
little, as the air introduced carries off too much carbonic acid. 
A fresh supply of salt water, or of fresh water added to make up 
