1880 .] 
FRAME POTATOS. 
wliere the summer does not exceed two 
months, during which period the sun scarcely 
sets. 
The effect of electric light upon flowering 
plants is very striking, being apparently more 
efficacious to bring them on than sun-light. 
Although the amount of heat given off from 
the electric arc is not great compared with a 
gas flame, yet the rays of intense heat of the 
arc counteract that loss of heat by radiation 
from the leaves into space which, during a 
clear night, causes hoar frost. For this reason 
it is inferred that electric light may be usefully 
employed in front of fruit walls, in orchards, 
and in kitchen gardens, to save the fruit buds 
at the time of setting; and in this application 
electric light will probably be found a useful 
agent not only to promote rapid growth, but 
to insure a better yield of fruit. Experience 
alone can determine absolutely the effect of 
electric light upon the ripeningof delicate fruits, 
but considering its evident power to form chlo¬ 
rophyll, there seems no reason to suppose that 
its action would not also in this case resemble 
that of the sun, and that saccharine matter, 
and more especially the aromatic constituents, 
would be produced. - 
At the subsequent meeting of the Royal 
Society (March 18th), Dr. Siemens exhibited 
Strawberries which had been ripened under the 
influence of the electric light, and both colour and 
flavour proved to be well developed. Two pot- 
plants were shown which had been exactly 
alike a fortnight before. The one had been 
exposed to the electric light, and now bore many 
ripe fruit, while the other, which had been ex¬ 
posed to solar light only, though kept at the 
same temperature, had all the fruit as yet green 
and unripe. 
The most effective height at which to place 
the naked electric light of 1,400-candle power, 
is, according to these experiments, about 2 
metres. By using a metallic reflector, and 
thus throwing the major portion of the upward 
rays down upon the surface to be illuminated, that 
height may be taken at 3 metres. This power 
costs 67 cubic feet of gas per hour, say 4d. per 
hour, or, including attendance, 6d. per hour. 
Greater power would be relatively cheaper. 
The cost of electro-illumination as applied 
to gardening purposes depends very much on 
the scale on which it is applied, and partly on 
the cost of fuel, or other source of energy. To 
work only one electric lamp by means of a small 
steam or gas-engine is expensive, both in fuel 
and in cost of attendance. Experience in elec¬ 
tric illumination has established a form and 
size of machine, both convenient and suitable 
for the attainment of economical results, viz. 
the medium dynamo-electric machine, which 
if applied to a suitable regulator, produces fully 
6,000 candle-power of diffused light, with an 
expenditure of four horse-power. 
In operating upon an extended surface, several 
lamps should be placed at such distances apart 
as to make the effect over it tolerably uniform. 
Nine lights placed at distances equal to three 
times their elevation, or 18 metres, would cover 
an area 54 metres square, or just about three- 
quarters of an acre. If this space were en¬ 
closed with a high fruit wall (as shown with 
the lamp-centres marked in the accompanying 
sketch), this will also get the full benefit of 
electric radiation, and would serve at the same 
time to protect the plants from winds. 
The engine-power necessary to maintain this 
radiant action would be 9 x 4=36 liorse-power, 
involving the consumption of 36 x 2-^—1)0 lb. 
of fuel per hour, or say for a night of twelve 
hours—with an allowance of 40 lb. for getting 
up steam—10 cwt., which, at 16s. per ton, 
would cost 8s. 
FRAME POTATOS. 
GwOT has long been a moot-point between 
& K various schools of potato cultivators, 
Q-Al observes a writer in the Gardeners' 
Chronicle, as to whether deep or shallow 
planting is best adapted to the nature of the 
potato, and which is most calculated to pro¬ 
duce a good crop of tubers. As far as regards 
the best method of planting frames for the 
obtaining of early forced crops, the practice 
long adopted in Lord Londesborougli’s garden 
seems to present very strong evidence of the 
value of shallow planting. Mr. Denning, we 
are told, plants all his potato tubers intended 
for frame work in small pots, with the top 
of the tuber just projecting from the soil. 
In this way, only those roots that are de¬ 
veloped at the base of the shoots are 
enticed into the soil, whilst all the tuber 
rootlets remain exposed to the air. When the 
plants are about eight inches in height they 
are planted out in frames, ten inches apart 
each way, the tuber rootlets being just buried. 
The stems afterwards receive two earthings of 
added soil, each about one inch in thickness; 
and, as the result of this mode of culture, the 
young tubers are found to be produced finer 
and far earlier, and there is a better and more 
regular crop, than is found when the tubers 
are planted perhaps from four to five inches 
