Vol. XXV. No. 9.] 
POPULAR SCIENCE iq"EWS. 
137 
M. Girard's various experiments in the study of 
growtli, etc., and, in fact, for practical purposes, 
tlie practical advice is certainly the most useful 
part of his work. So I atjstract his advice to 
those wlio are interested in the matter and are 
foi-tunate enough to have a potato-field of their 
own. 
First of all, it seems that the nature of the soil 
is of small importance. Potatoes generally thrive 
in all sorts of soil, unless exceptionally bad, or 
exceptionally poor as concerns some chemical 
constituents — such as phosphoric acid, potash, 
and nitrogen. But the physical condition of the 
soil is important ; it should not be too heavy. As 
everyone knows, potatoes yield a large number of 
radicals, and these cannot develop unless the soil 
is light and permeable. So a good ploughing is 
necessary — not a slight, superficial one, as is often 
the custom of French peasants, but a deep one of 
some thirty or forty centimeters (twelve or fifteen 
inches). Manure is more or less necessary, ac- 
cording to the chemical composition of the soil, 
and on an average it will be well to use the fol- 
lowing manure : 
Superphosphate 62 parts 
Sulphate of potash 23 " 
Nitrate of sodium 15 " 
Of this mixture one must use from 500 to 800 
kilograms per hectare, more or less according to 
cases. A very common error consists in choosing 
for planting, tubers either very large or generally 
very small. This practice must be abandoned, 
and care must be taken to select average-sized 
tubers yielded by strong plants. Another com- 
mon practice consists in cutting up the tubers, 
and to make of one, four or five. This must never 
be done, as the crop is always inferior in amount. 
Whole tubers must always be used; it is more 
profitable. 
'J'he time of year for planting is between March 
15 and April 15 ; not later ; earlier is useless. The 
planting must be quite regular, and the distauce 
between successive files, or rows, has much im- 
portance. The parallel rows should be sixty centi- 
meters (two feet) apart, and in each row the tubers 
should lie planted fifty centimeters apart. These dis- 
tances are 'reasonable ; if diminished or increased, 
inferior results follow. In France it seems there 
is a tendency to plant at too large distances apart. 
Good care must be taken to weed as usual, to 
build the little mounds everyone is acquainted 
with, and if the blight comes one must be ready 
for it. A good remedy consists in : 
Water 100 liters 
Sulphate of copper 3 kilograms 
Lime 3 " 
Use 1,700 or 1,800 liters per hectare. Never un- 
earth the potatoes so long as a single green leaf 
remains on the stalk. A single leaf is enough to 
keep the tubers increasing in weight, and it is 
useless to prevent them from doing so. But as 
soon as the leaves have all withered, the time has 
come for the harvest; it is useless to keep the 
tubers any longer in the earth. 
Such are the advices given by M. Girard, and 
the persons who have followed them have seen 
their crops become double and even treble what 
tliey used to be with the ordinary routine process. 
Numerous amusing instances of the real import 
of every particular have been yielded by the pro- 
ceedings of some cultivators, who, while follow- 
ing M. Girard in some points, have deemed it bet- 
ter to follow their own ideas on others. The 
result has always been immediately apparent, 
consisting in a serious falling otf of the crop, 
when, for instance, neglecting the directions as 
to distances, or preferring halves or quarters of 
potatoes to whole ones for planting. It must be 
added that M. Girard's advices are not based on 
experiments only, but that they have been fol- 
lowed in many parts of France, in the field, and 
not in mere experiment stations, and that they 
are all the result of a careful investigation. 
Farmers in all parts of the world can profit by 
them. 11. DE V. 
Paris, France. 
rt)riKlnal in POPULAR SCIENCE News.] 
THE GIANT SLOTHS OF THE PAST. 
BY KATHARINE B. CLATPOLE. 
PART 11. 
While the South American megatherium and 
mylodon received their names from two of Eu- 
rope's most eminent anatomists, it was a distin- 
guished politician, no other than Thomas Jeffer- 
son, twice President of the United States, who 
stood sponsor for the first of the ancient ground- 
sloths found in this country. At the time of the 
discovery of the gigantic half-fossil bones in a 
cave in Oreenbriar County, West Virginia, .Teffer- 
son was President of the Philosophical Associa- 
tion founded at I'hiladelphia by his friend, Benja- 
min Franklin. To him, therefore, were sent a few 
of the bones, among which three enormous claws 
were so conspicuous that he at first sight regarded 
the animal as " appt^aring to be of the tiger, lion, 
and panther species." Later, however, he an- 
nounced only "the discovery of certain bones of a 
quadruped of the clawed kind," suggesting for 
the remains a name compounded of two Greek 
words — megalas, large, and onyx, a claw. So suit- 
able was this designation considered that it was 
afterwards adopted by Dr. Wistar in his account 
of the bones ; and when later they were de- 
scribed by Dr. Harlan, he also retained the name, 
adding to it Jeffersonii to commemorate the il- 
lustrious man to whom the happy appellation was 
due. 
Remains of the Megalonyx Jeffersonii have come 
to light but slowly, and, until recently, in too 
fragmentary a condition to build up a skeleton 
therefrom. In December, 1890, however, at least 
a third of the required number of bones were dis- 
covered in excellent condition in Holmes County, 
Oliio, in a swamp to the northeast of Millersburg. 
Excavation, suspended by the oncoming of win- 
ter, may yet disclose more of this great animal 
and some fortunate museum become the owner of 
its complete skeleton. Meanwhile the discovery 
itself is of special significance, not only in the his- 
tory of the megalonyx but of the whole family to 
which it belongs. Megalonyx Jeffersonii, not 
hitherto fouud north of the Ohio excepting on the 
Atlantic coast, is now known to have extended its 
wanderings at least one hundred miles further 
northward in the valleys of the Ohio, and no little 
light is thrown on the question of the length of 
time that has elapsed since these huge edentates 
were denizens of North America. 
The swamp, formerly one of those glacial 
lakes with which the front of the ice-sheet 
abounded, consists of peat to the depth of from 
five to ten feet overlaying a bed of marl formed 
by the deposition of silt from the glacier water. 
In its uppermost layer only, this marl contains a 
multitude of snail shells, showing that it was not 
till the ice-tongue had retreated to return no 
more, and ice-cold water had ceased to enter the 
lake that the water-mollusks appeared upon the 
scene. With them came water-plants such as are 
to be found in the Ohio swamps today, and an- 
imals that had been driven southwards by the ice, 
began slowly to return. Summers of exceptional 
warmth would even tempt hither some strange 
beasts from farther south. Among them, doubt- 
less, were the megalonyx whose remains were 
fouud near Millerslpurg, between a tongue of 
gravelly drift that projects into the swamp and a 
small island of the same material. As its hind- 
quarters were farthest from land the animal seems 
to have been swimming from one point to the 
other and, in attempting to land in the weedy 
shallows, to have been held fast by the shell- 
marl on which its bones were lying. The time 
of its death must thus have been after the final 
retreat of the ice had allowed the return of the 
snails whose shells abound in the upper layer of 
the marl. It must also have been long enough 
ago for the water-plants to form a peaty mass of 
five feet thickness above the bones. For this 
a space of six to seven thousand years will suf- 
fice. This discovery in Ohio, therefore, makes the 
megalonyx and his congeners, the megatherium 
and mylodon, creatures of yesterday, counted by 
geologic time. Contemporaneous with the mas- 
todon they were, in this western world, among 
the foes of primitive man and that even after 
civilization had begun to dawn in the far west, on 
the rich plains of the Nile. 
The western world was the home of the gigan- 
tic extinct edentates as it is now that of their 
modern representatives, but although half fossil 
remains of the former are found from time to time 
in North America, the Southern continent must 
be considered to have been their favorite habitat. 
This fact was fully demonstiated by Charles 
Darwin when, as a youth, he visited Patagonia 
and Buenos Ayres, as naturalist to the expedition 
of the Beagle. Excited by the accidental dis- 
covery of some fossil bones of a gigantic edentate 
he prosecuted a most diligent and intelligent 
search for more. Often did he spend whole 
nights in the work of resurrection, but more often 
he was compelled to return to the ship after only 
a few hours labor, breaking off in despau- the 
projecting extremity of some huge, partly exca- 
vated bone. The occurrence of these enormous 
bones was indicated to him in various ways, some- 
times in local names such as " the stream of the 
animal," " the hill of the giant." At other times 
a clue was given in traditions that ascribed to 
certain rivers the marvellous property of chang- 
ing small bones into large, and to certain bones 
the power of growing after death. By one means 
and another he became impressed with the ex- 
traordinary number of the remains buried in the 
grand estuary deposits that foi-m the Pampas, 
coming to the belief that the whole area is one 
wide sepulchre of extinct, gigantic quadrupeds. 
In the north of Patagonia he actually excavated 
such a catacomb, finding in a space of about two 
hundred square yards, the remains of nine extinct 
giants, six of which belonged to the family of 
edentates. 
The wonderful resemblance borne by these co- 
lossal edentates to the sloths and armadillos still 
inhabiting South America arrested the attention 
of the young naturalist and turned his thoughts 
to questions regarding the appearance of organic 
beings on our earth and their disappearance from 
it. It was indeed the vivid impression made on 
his mind by excavating these fossil edentates with 
his own hands that formed one of the chief start- 
ing points for his speculations on the origin of 
species. These giant sloths have, therefore, apart 
from their intrinsic interest, a value that is almost 
sacred in every department of thought, being con- 
nected with one of the broadest generalizatious 
that the world has ever known. 
