374 
THE TROPICAL AGRICULTURIST. (Dec. 1, 1903. 
remarkably free from admixture with vegetable or 
mineral impurities, and it would, no doubt, be suit- 
able for any purpose for which the latter is employed. 
At present, however, the material is of relatively 
small commercial value. 
Two specimens of the mineral substance used in 
the preparation of Getah Jelutoua; were supplied : 
one of the mineral as imported, the other of the 
material prepared for use by heating. 
The mineral proved to be a specimen of the fibrous 
variety of gypsum, known as " satin spar" (hydrated 
calcium sulphate); it was white, translucent, crystal- 
line and massive. 
The specimen which had been heated was white and 
opaque; it was non-crystalline, but retained the 
fibrous form of the mineral, and readily crumbled 
to powder in the fingers. It absorbed wa,ter, but did 
not set like plaster of Paris. It contained only 2'48 
per cent, of water, so that in course of preparation 
the gypsum has probably been heated to a high 
temperature, with the result that the product does 
not set when mixed with water. 
If, as is indicated, the addition of this substance is 
essential iu the preparation of the gutta, it is prob- 
ably due to the fact that the latex ia coagulated 
by a solution of calcium sulphate, as is known to 
be the case with several other rubber latioes,— 
Board of Trade Journal, 
THE ROOT ROT OF TARO("CALADIUM 
ESCULBNTUM,") 
According to DeCandolle the taro plant is a native 
of India ; from which, country it, was transported first 
to Ceylon, Sumatra; the Malay Archipelago and Egypt, 
and more recently to the I'lji Islands and New 
Zealand. From New Zealand it undoubtedly accom- 
panied the present native Hawaiian race in its 
migration to Samoa, Tahiti, and finally to these Islands. 
The plant has been in cultivation so long that there 
are many cultural varieties, differing from one another 
in size, maturity, form and habit of growth, and 
especially in the coloring of the flesh of the swollen 
root or oorm, the portion of the plant which is mainly 
used for food, and the varieties resulting from cultiva- 
tion have become so fixed, that they now have nearly 
the same value as separate species. In Hawaii there 
are two distinct individual strains of taro, the one with 
red or pink flesh and the other white. Of each of 
these strains there are many sub-varieties or forms, each 
with native names. A list of such rarieties is given in 
"Thrum's Annual for 1888," enumerating twenty-eight 
in all. Later lists give as high as forty-five separate 
forms or strains known to the Hawaiian people. Taro 
holds about fourth place among the products of Hawaii, 
at least in area of land devoted to its cultivation and 
probably also in total value of crop. The investment 
in taro growing approximates from $450,000 to $500,000. 
It is practically all consumed in Hawaii, the export of 
, taro flour or " Taroena," amounting to but a very 
small percentage of the total crop. 
Usual Method of Culture— Taro is cultivated in 
Eatches of varying size. Bach patch is surrounded 
y a dyke containing openings admitting water and 
allowing its exit. These patches are usually extremely 
irregular and depend on the contour of the land both 
as to size and shape. A valley containing one or two 
square miles will have, perhaps, two or three hundred 
taro patches or fields, and hardly two of these will be 
exactly alike in size or shape. Before planting the 
taro the water is allowed to drain off the fields ; the 
ground is then dug up, or pkwed with a rice plow, and 
is fertilized with the leaves, stems and trimmings of 
the previous crop. In this way the taro rot is perhaps 
often transferred to new fields, through the use of the 
trimmings of diseased plants as fertilizer. Occasion- 
ally stable manure is u«ed, or rarely, a complete 
fertilizer. These are thoroughly mixed with the soil, 
Taro is propagated by means of the crown of the plant 
with its accompanying leaf stalks, At the time the 
crop is harvested, the upper portion of the root is cut 
off with a knife, then the leaves themselves ire cut off 
leaving about six inches of leaf stalk on the er«wn of 
the root. These tops, called "hules, " trA either 
planted in a circle around a little mound of tirt, or in 
rows across the field. They are usually placed about 
one foot apart. As soon as the patch is planted water 
is again turned on, but only enough is used to keep the 
hules moist until the roots start. The patch is not 
flooded. In about a month after the hule has been 
planted the roots start, and the crown throws out new 
leaves. The period of maturity varies according to the 
variety, ranging from twelve to fourteen months or 
more, from the time the hule is set iu the ground. 
Cultivation consists in keeping the patch clear of 
weeds, and the soil between the roots is sometimes 
stirred with pick or shovel, care being taken not to 
loosen the roots, 
Tabo Rot,— The lowland taro, or that which is 
grown entirely under irrigation, suffers a great deal 
from a disease known as " taro rot." The disease 
appears to be of two forms, one of which is due to soil 
oonditions or lack of drainage. The other is of a funeus 
or bacterial nature, and is due in part at least to the 
planting of diseased hules. The rot is first observed 
in the patches when the plants are about two months 
old, usually making its appearance on small or poorly 
nourished hules, or on those which are improperly 
planted. The disease is entirely local." The losses 
throughout the Hawaiian Islands due to the disease 
amounts to at least $70,000 per annum, and the disease 
seems to be on the increase. 
Conclusions.— The conditions necessary to secure 
ajgood crop of taro, are : 
(1) A supply of good hules free from disease. 
(2) A patch so laid out as to secure the most econo- 
mical use of the irrigation water, 
(3) The application of proper fertilizers at the right 
time. 
(4) A constantly running stream of water circulat- 
ing over the fields, or when this is not possible, a 
frequent change of water. 
(5) An occasional change in the variety of the taro 
planted. 
(6) An entire change of hules from one patch to 
another, or a rotation of crops, using taro land for rice 
or bananas, at least two years in every five.— Pia«iers' 
Monthly. 
DANGEES OF ELECTEICITY. 
HOW TO AVOID THESr, 
By Sydney F. Walkeb, e.n., m.i.e.e., Etc, Etc. 
The accidents at the Fulham baths illustrate the 
dangers incident to the use of electricity, and a con- 
sideration of them and others of a similar nature show 
how easily tne dangers may be provided against. 
Electricity is coming more and more into our 
daily life. It is entering more and more into all onr 
manufacturing processes, and its use iu every instance 
means either greater comfort or cheaper production. 
But there is one thing necessary in order that the 
increasing use of electricity may go on, and that is 
that it shall be produced and delivered to the consumer 
at a cheap rate, and for this purpose it is necessary 
that higher and higher pressures shall be made use of, 
The Perils op High Pbessurb. — High pressures 
enable electricity to be generated at places where 
energy can be obtained cheaply and to be transported 
cheaply to wiiere the consumer requires it; and it ia 
not only the very high pressures, such as are used for 
transporting electricity in large quantities that are 
economical. What may be termed high domestic 
pressures enable current to be delivered to private 
houses, ofiices, warehouses, etc., at a cheap -r rate than 
lower pressures, and this is the reason that in almost 
every town, as soon as incandescent lamp makers 
were able to produce a really practical lamp at 200 
volts, the lighting service vrae altered to that fignre> 
