Deecmber i, 1887.] THE TROPICAL AGRICULTURIST. 
ition. so the ontire body of plants or animals can be 
found in these deposits. 
In the jurassic age, or epoch, the process of iossiliz- 
ation was similar, only the saturatiug liquid was a 
warm spring water containing lime, etc. 
The second division is again subdivided : —First we 
know that oarbondioxide (CO,) becomes liquid by 
pressure and in this state it flows through the cracks 
formed in the earth and by its presence the rocks 
are cooled; at last it comes in contact with already 
reduced elements which absorb oxygon readily and 
carbon is set free again. This process will cool down 
tho metal bath and subterranean water flow into the 
cooler chambers and float the carbon off into pockets 
or vaults already formed by previously described 
changes. These subterranean basins (pockets) have 
been by another revolution filled with a forest, and 
now these trees and plants are immediately saturated 
with oils and carbon, and so decay is chocked, tho 
spaces between tbem are filled with carbon ; by means 
of pressure the carbon becomes successively compact ; 
marsh gases are produced which escape and form 
again mineral oils. During the passage through the 
channels at last tho oils become solidified, their quality 
depending upon tho region and materials through 
which they flow. These deposits by certain ages and 
influences becomo dry, so that the whole process re- 
sembles a fractionate distillation. All soris of coal 
and asphaltum are liable to be formed, depending 
entirely on tho character of the stoppage or con- 
densation to which they are subjected. Also gilsonto, 
so-called which is nothing else than a dry specimen 
or small deposit of albertite on the surface, which will 
chauge as soon as depth is gained. I could easily 
refer to coal beds in this country, where the truth 
of this theory can be seen, but I am not willing to 
occupy so much space in writing out examples. I 
only wish that this article may bring forward scien- 
tists to a closer and a more impartial investigation 
of this subject. 
Furthermore, I will state that all other formations 
depend upon this process, but they are due to springs 
and volcanic actions of which I will speak another 
time. — Chicago M'uuwj Heview. 
♦ 
FISH CULTURE. 
Tho subjects of fish culture and fish acclimatis- 
ation have, during the last quarter of a century, 
received extraordinary and well-deserved attention 
from nearly every nation in Europe. Tho Americans, 
with their usual energy and go-aheadism, took up 
the matter, and wore soon in advance of those who 
had had a long start of them. In the United States 
fish culture is regarded as a national business, and 
is carried out on a scale of groat magnitude. AYhile 
other nations are hatching out ova by tens of thou- 
sands and hundreds of thousands, the Americans are 
dealing with hundreds of thousands and millions, for 
they havo rightly judged that in order to do the 
business thoroughly it must be carried out on a largo 
scale. Congress votes large sums annually, and many 
of the States, as well as private individuals, contri- 
bute! liberally. A largo number of intelligent and 
enterprising men havo devoted themselves to the work 
with singular wholeheartedness. The results havo been 
eminently successful, rivers and lakes that had he- 
BOme depleted, or uenrly so. now teem with fish of 
the best kinds ; shad, which tho Americans appear 
to regard as the mo«t important of their fishes, 
salmon, trout, alewifc, white fish, pickerel, and other 
choice kinds, now abound in waters in which they 
wore, not very long ago, scarce or entirely absont. 
No troublo or exponso is considered too great to 
introduce new fish, or to distribute wcllknown anil 
approved sorts. Tho Sulmo hucho, Danube salmon, 
is imported from Germany, and tho Sdlmo quinnat i» 
brought by rail nil the way from (Vifnrnia, nnd 
with UMMMi Aquarium curs are frequently attached 
to tr»im, and I have been informed by travellers 
that on the journey between tho Knstern States and 
an Francisco it is no rare occurrence for a train 
to stop near a lake, river, or rivulet, and an attend- 
ant to hurry down to the water with a tin em or 
two of fish which he liberates and immediately re- 
turns. In this way vast numbers of fish are distri- 
buted iu the most expeditious manner over an ex- 
tensive area aud at comparatively littlo cost. On 
one occasion a river became iu a curious manner 
stocked with fish. A train iu passing over a bridge 
met with an accident, several carriages, including an 
aquarium car containing a large quantity and variety 
of fish were precipated into the stream, which thus 
received far more than its intended quantum, aud 
was soon afterwards found swarming with fish. The 
American fish culturists are now directing their at- 
tention to the artificial propagation of sea fish —which 
exhibit signs of exhaustion — with satisfactory results. 
In England fish-culture is making steady progress. 
It does not appear that the business is aided pecu- 
niarily by the Government, probably because private 
enterprise is found sufficient. By far the most im- 
portant fish-cultural establishment in Great Britain is 
that of Sir James Maitland, at Howietown, in Stir- 
lingshire, on which over £12,000 has been expended. 
Exhaustive experiments have here been carried out, 
and the long-vexed question whether the Parr is a 
salmon or not has been decided iu the affirmative. 
The curious fact of the reproduction of hybrids haB 
been established. It has also been found, us iu tho 
vegetable world, that individual fish improve with 
culture ; not only are the fish themselves finer but 
their ova is larger than with fish in their wild state. 
At Howietown large numbers of salmon and trout 
ova are yearly hatched and distributed. The estab- 
lishment is conducted on commercial principles, aud 
has been managed with sufficient judgment aud skill 
to prove a financial success. 
The oldest fish-cultural establishment in Europe is 
at Commachio, iu Italy, on tho Adriatic. The lagoons, 
which were at one time dreary wastes, ruu paralled 
with the sea; they are about 130 miles iu circum- 
ference, and aro divided into 140 basins, surrouuded 
with dykes, and are all in communication with the 
sea. Eels abound there to such an oxtent that the 
inhabitants sell them throughout all Italy. During 
the months of February, March, aud April the gates 
are left open and all the passages free; the young 
eels enter of their own accord, and the more abund- 
antly as the weather is stormy. Once iu the basins, 
the fishes find nourishment so abundant, and so well 
suited to their wants, that they do not at'empc to 
leave until full-grown — that is, about five or six years, 
when they return to the sea to spawu. The lagoons 
yield about 1000 tons of eels annually, and a net 
revenue of nearly £20,000. In some parts of Ireland 
the eels fisheries are second in importance only to 
the salmon. In London the eel ranks with salmon, 
turbot, sole, aud a few others which are termed 
" prime," aud realise about Is. per lb. It is a fish 
that could, I think, be successfully, and with little 
difficulty, introduced into our waters. There are some 
twenty-five species of eels ; the one recommended, 
and which we should be careful iu procuring, as it 
is by far the best, is commonly known as the silver eel, 
France, Germany, Belgium, Russia, Swedou, 
Norway, Switzerland, and other couutries in Europe 
have achieved great results of late years in fish cul. 
tare. To one establishment alone is there soaoo for 
a brief reference — namely, to the celebrated fish f irm 
at Hiiningue, founded by tho French, but now in tho 
possession of the Germans, who carry it on with 
surprising energy. The success of this establishment 
was at first mainly due to tho exertions of tho dis- 
tinguished M. Coste, a man of hi ,h scientific attain- 
ments as well as of singular practical ability ; under 
his direction it soon becamo the loading fish cultural 
establishment in tho world. Many of the exhaust' I 
rivers of Franco were speedily stocked with fish, the 
fi-hiug industry revive.!, and the revenue derived from 
the river fisheries became greatly augmented. With 
coniMiondablu liberality tho Frouch Government ex- 
tended the benefits of Huuinguo to other nations, 
young fish and ova being sent thouco to various parts 
of Europe. 
