January i, 1892.] 
THE TROPiCAL AGRiCULTURIST. 
477 
of the nature of the substance of which he was 
the fortunate owner. The barrelful proved to be 
ambergris of very fair commercial quality, and 
was disposed of with careful management, at the 
full market value of the day, the broker wisely 
never hinting to anyone until the last piece was 
sold how groat was the quantity entrusted to his 
care, for fear of spoiling ihe market. 
The greater part of the ambergris sold in London 
durirjg the last fevv years has been that obtained 
by the New Zealand and l'asaian;in whalers who 
ply their trade in the Antarctic Ocean. Whale, 
fisiiing was onco an importiint industry in Tasma- 
nia, and quite a large fleet of whalers was owned 
by Hobart firms. Now the Tasmanian industry has 
practically ceased to exist, and there is no hope 
of its revival. New Zealand still possesses fisheries 
of some importanca, and will probably continue to 
supply our market with much of its ambergris for 
many years to come. Meanwhile spermaceti whales 
are getting scarcer year by year, and the time may 
soon come when the scarcity of ambergris shall be 
ohronio instead of spasmodic. It is to be hoped 
that before that date science will have taught us 
how to supplant nature in the production of amber- 
gris ; but at present there are no indication what- 
ever of an efficient synthetic substitute — Chemist 
and Drugijist. 
— - — 
NOTES ON POPULAR SCIENCE. 
Dr. J. E. Taylor, f.l.s., f-g.s., &c., 
Editor or "Science Gossip." 
Professor Bailey, an Ame-ican botanist, has been 
reporting on the experiments receatly made at the 
station connected with COrneU University with 
electricity. Professor Lodge, one of our own most 
eniiueiit scientist", some years ago showed that the 
electric liglit dispelled fog. A report on foe just 
published demoastrates how injurious it is to plaut 
healthiness. Hence, if we can'.dispel fog, and at the 
same time stimulate the growth of plants by electricity, 
the latter will be doubly useful. Professor Bailey's 
experiments were made during January, Feburary, and 
Maroh, one forcing-house being exposed to the normal 
light of the fiky during daytime, and illuminated by 
electricity at night. Another forcing-house contamiug 
the tame bind of plants, was not lit at nig-ht. The 
difference in the results was so marked that the 
experiments have bean continued this year with a 
view to noting the effects on colour. 
Two distinguished French chemists have just read 
a paper before the Paris Academy of Sciences on the 
" Proper Odour of Earth." Everybody in the oouetry 
is well acquaiuted with the delicious smell the earth 
yields after a shower of r.iin. This is now found to 
be due to an organic compound of the aromatic 
family. Its odour is very penetrating, and analogoas 
to that of camphor. Its proportiou iu the so;l is, 
however, only a few millionths of a grain — indeed, 
one threcraillionth gives a decided smell. Tho new 
priocipleis neither acid, alkali, nor a normal aldehyde. 
Its concentrated aqueous solutions may be precipitated 
by carbonate of potassium with the productioa of a 
resinous ring. When heated with potash, an acrid 
odour analogous to that of tho resin of aldehyde is 
developed. Under certain conditions, such as by tho 
employment of potash and iodine, iodiform is produced. 
This property is common to miny other substances, 
but aloohol, acetone, &c., were not found during the 
experiments just meutionei, although smio chemists 
statu they have been met with in vegetable mould, 
Here is good news for potato grower.-!. It bus long 
been known that a solution of sulphate of copper 
checked mildew in vines, and an experienced French 
agricultural chemist determined to try the effects ou 
the allied species of fungus which causes potato 
disease. He has been trying it ou the potato plants 
for two gummera past, and h«B ruceutly published a 
lengthy statement of the experiments, which are of a 
very remarkable character. He shows that an appli- 
cation of sulphate of copper not only checks the ravages 
of the disease, but vastly inert ases the crop — iu some 
instanceu to the extra, value of £5 an acre. 
Tho fascinating ard importast problem as to the 
acquiaitiou oi nitrogen from the atmosphere by plants 
is still occupying the attention of chemists, "both in 
this country, America, and Fra' ce. In the United 
States two eminent investigators have arrived at tbe 
conclusions that atmospheric nitrogen is undoubtedly 
acquired during the growth of peas and alfaJfi), and 
that the amount of nitrogren gained incr(;a-os with 
the number of root tubercles. Further, liiat the 
addition of soil-infusion is not necessary for tbe pro- 
ductioa of root-tuborcles — a fact which may be accouu ted 
for by supposing that the micro-organisms or their 
spores exist iu the air, and are deposited in the pots 
where the plants grow. Cereals do not, as a rule, 
manifest the power of acquiring the nitrogen from 
the atmosphere, aoc are root-tubercles formed ou them, 
as in the casa of leguminous plants. The latter fact 
disproves the statement recently made by a Freuch 
agricidtural chemist, that cereals have the power of 
absorbing atmospheric nitrogen. Professor Gilbert has 
also arrived at the conclusior, that} free nitrogen is 
fixed in the course of the development of the organisms 
within tho nodules, and that the resulting nitrogenous 
compound.s arc absorbed and utilised by such leguminous 
host-plfints as the common red clover. 
Dr. .John Murray has read another paper before the 
Royal Society of Edinburgh on the much-disputed 
subject of silica and siliceous formations in modern 
seas. The facts are of great interest to geologists 
generally. There is greit difficulty in accounting for 
the number of organisms which secrete silicic acid, 
and for the remains of such organisms which occur 
in and on the bed of the ocpan. The amount of silicic 
aeiil which exists in solutiou in sei-water is far too 
small to account for the immense development of such 
organisms in various parts of the ocean. Dr. Murray 
and Mr. Irvine have proved that clay and mud carried 
down by rivers to the sea are to be found in even 
the le.ast disturbed parts of the ocean. Diatoms can 
extract from these clays sufficient material for the 
formation of their flinty sheila. — Australasian. 
HOW TO SET A HEN. 
It may seem to be an easy matter to many to do 
this seemingly simple piece of work, but it is indeed 
a thing that requires forethought, experience and great 
care. To set a hen so as to secure be^t results is 
indeed no child's play. In the first place, be sure 
jour hen wants to sit. Theu be sure she is in a good 
location ; if not, move her to one. If she can be set 
on the ground, you will find it to be the very place ; 
if not, cut a sod, turn it over, scoop out a dish like 
place, ihen put the sod in a box, grass side down. A 
ne.st made in this way will hold moisture — one of the 
reasons why a hen sitting on the ground always 
hatches better than when up in a building. Sprinkle 
a little litter over the nest and put in your eggs. 
Always have the nest arranged so th»t the heu can 
walk on and not fly down npou the eggs. If you breed, 
the heavy varieties the best nest can be made by turning 
down a barrel with only one head out and scooping 
out a place in the ground so the barrel may be sunk 
in the ground a little. The hens Can then walk on 
their eggs without danger of breakage- The ground 
will help to secure moisture for the eggs, and you 
can close the open end of the barrel every night, 
preventing rats from interfering. Take the hen off 
every day or two to give the eggs an airing, if tho 
hen does not go oft" on her own account. 
Be sure and set your hens in such a way tha; other* 
cannot interfere. Jlark the eggs, so that if others 
lay with the hen you can remove the fresh ones. 
After a week, test the eggs to see which arc fertile 
and which are not. It is not your policy to have in 
the nest eggs that will not hatch. After removing 
the unfruitful egg.s you can replace them with fresh 
ones, marked, and upou tbe first ones batobiog, the 
