SCIENCE. 
241 
changeable with them. In this view inertia is a law of 
energy and not a property of matter. 
The following table gives a synoptical view of the 
various forms of energy and the names they have. 
Where there are no names an interrogation point is 
placed to indicate the lack. To the writer it appears 
as if each specific form of energy should have a spe- 
cific name, but he is aware of the difficulty of finding 
suitable names and getting them adopted. If this 
want is felt by others then a committee of suitable 
persons might be appointed by the American Associa- 
tion for the Advancement of Science, who might con- 
sider and recommend appropriate names as did the 
British Association for Electrical Science some years 
ago. 
TABLE OF FORMS OF ENERGY. 
i. Mechanical or Molar Motion. 
Form. Name. 
f Rec'ilinear ? 
Rotary ? 
my ' 1 (vibratory Sourd. 
2 I Curvilinear ? 
Spiral ? 
[ Vortical ? 
2. Atomic and Molecular. 
f Rectilinear Free path. 
I Rotatory Electricity. 
_ my^ (Vibratory Heat. 
2 ] Curvilinear ? 
Spiral ? 
Vortical ? 
3. Atomic and Molecular. 
£' -£ = e 
(? Specific heat. 
< ? Latent heat. 
( ? Specific Indue. Capac. 
£ = ? 
4. In Ether. 
( Rectilinear 
Vibratory 
Pulsatory . 
Undulatorv 
Rotatory, ) Circularly and 
Curvilinear, £ EllipticaLy 
Spiral 
^Vortical 
? 
. .Chemism. 
. . Radient Energy. 
( Light. 
Pseudo e Heat. 
^Actinism. 
^ . Polarized Light. 
. . . Magnetism. 
. . .Matter. 
THE SPANISH MACKEREL AND ITS ARTIFI- 
CIAL PROPAGATION. 
By Chas. W. Smiley. 
Tnis fish, Cybium Maculatum, is in general appear- 
ance very like the common mackerel. It is larger, how- 
ever, averaging seventeen to twenty inches in length. 
When first described it did not exist in our waters, but 
was abundant in the Gulf of Mexico and the Caiibbean 
Sea. Its first appearance was about 1850. It then began 
to be taken as a food fish. It began to be caught in the 
Chesapeake about 1870. About 1872 or 1873 it appeared 
in Narragansett Bay, when three or four hundred were 
taken at one haul of the seine, but the fish did not sub- 
sequently reappear. 
The Chesapeake Bay has been annually visited by 
large schools for several years, where it is known as the 
“ Bay mackerel.” None were known to have been mark- 
eted there prior to 1870, but in 1879 1,300,000 of this fish 
were sold, and the season of 1880 is expected to yield 
2,000,000. They were taken in pound nets and gill-nets. 
At Cherrystone, Md., there are fourteen pounds, which 
average a catch of 500 to a day. As many as 4,000 per 
day have been taken in a single pound on the eastern 
shore of the Chesapeake, while 2,500 is not a rare catch 
with one pound. The Bay fish are, however, smaller 
and leaner than those caught further north. 
As this fish refuses the hook its capture is limited to 
pounds and nets. The first pound in the Bay was built 
in 1875. Now there are 164. The first gill-net used 
there was in 1877, while now there are 175 men fishing 
by this means. A net 100 fathoms long will average 
forty fish per twenty-four hours, the fish weighing from 
one and a half to two pounds each. 
In the New York market the price per pound ranged 
from eighteen to thirty cents during 1879 ! for May, 1880, 
from fifteen to forty cents ; but owing to the large ship- 
ments in June the price fell to ten to fifteen cents. On 
special occasions the fish have been sold readily at one 
dollar per pound. The catch of 1873 at Newport, R. I., 
was sold at prices varying from seventy- five cents to one 
dollar per pound. 
This fish usually appears in the Chesapeake in May, 
when the temperature has reached 65° or 70°, and the 
number increases until the middle ot June. They remain 
abundant until September, and diminish as the tempera- 
ture of the water falls, until, in early October, nearly all 
have disappeared. They come in small schools, but later 
get scattered, and often quite isolated. Before leaving, 
the schools seem to be somewhat reformed. 
The United States Fish Commission, under the man- 
agement ot Professor S. F. Baird, the Secretary of the 
Smithsonian Institution, has long desired to experiment 
upon the artificial propagation ol this fish, but has been 
deterred by the lack of knowledge of its spawning time 
and places. These were both discovered June 1st by 
Messrs. Earll and McDonald, Assistants of the Commis- 
sioner. At that date the lower Chesapeake, especially 
Mobjack Bay, was found to contain large numbers of 
spawning mackerel. This opened the way for experiments, 
and Professor Baird was ready to seize upon the oppor- 
tunity. He directed Mr. Earll to make every effort to 
hatch some fish. 
June 21 Mr. Eat 11 started for Crisrield, Md., on the 
eastern shore of the Chesapeake, and during the follow- 
ing ten days there conducted his experiments. 
He found the number ot eggs produced by a single 
fish to be from 50,000 to 500,000, according to the size of 
the fish, the latter number having been taken from a fish 
weighing one and three-fourths pounds. Instead of all 
the eggs ripening at once, as is true in the case of the 
shad, only a part are thrown at a time, and at intervals 
of a few days, probably extending through two or three 
months. This is analogous to tne cod, which deposits 
its eggs at intervals during rive or six months. D fferent 
individuals of mackerel were found to vary in their time 
of spawning; some ripening a considerable time before 
others, and the males seeming to ripen somewhat in ad- 
vance of the females. From 40,000 to 130,000 eggs 
were obtained at one time from a single fish. The shad, 
however, yields only 20,000 to 30,000 as its fruits of an 
entire season. The cod, on the other hand, are so prolific 
that a twenty-one pound fish has yielded 2,700,000 eggs, 
and a seventy-pound fish has yielded 9,000,000 eggs. 
When the fish had remained in the nets several days Mr. 
Earll found that the most of the spawning females had 
deposited all their ripe eggs. The greatest quantities 
were secured from individuals that had remained in the 
pound but a few hours. It is believed that when con- 
fined the female presses against the netting in its efforts 
to escape and produces an abnormal discharge of eggs ; 
but it would result in the impregnation of a much larger 
number of eggs than would chance to be fertilized in a 
natural way. The males and females being caught side 
by side in considerable numbers, both eggs and milt 
would be present in the water in such quantities that 
