into the Rivers of Tasmania. 443 
nish with which they were covered inside. I have further, 
many proofs of the insulating properties of the varnish for 
the purpose. 
I have carefully read Mr. J. L, Burnett’s report, giving 
his views as to the defective state of the plans adopted by 
me. ‘To the 
Ist. I must beg to remark, that never having crossed 
the equator, I could only make strict enquiries of parties 
who had for information as regarded the heat against which 
I had to contend, and which was the only difficulty I had 
to fear in transmitting the embryo fish. I iearned from 
Captain Smith and many other parties, I might calculate 
upon the temperature of the atmosphere between decks at 
from 85 to 90 degrees under the line. Not contented with 
nor trusting to my own ideas of being able to keep the 
water at a lower temperature in the spawn-tub than that of 
the surrounding atmosphere, I applied to Professor Owen, 
our great philosopher in natural history, as well as to other 
scientific gentlemen, ‘The former gentleman also thought 
that ice would be of service placed in the spawn-tub, to 
keep the temperature of the water low ; but upon discussing 
the merits and consequences of ice to the spawn and brood, 
and also explaining my views, he agreed with me that my 
plan of evaporation, produced from the surface of the water 
by a supply of new water to the bottom of the spawn-tub, 
and arranged as I had determined upon, was likely to prove 
the best method. 
end. I perfectly agree with Mr. J. L. Burnett, that if 
atrangements could have been made to have the spawn-tub 
safely housed on deck, a far greater chance would haye been 
given to the spawn, in consequence of the greater circula: 
tion of air over the surface of the water; and I further 
