April r, 1882.] 
THE TROPICAL AGRICULTURIST. 
gix 
lato Dr. Seeman in his mission to these islands) on the 
means for combating the leaf-disease Hemileia. Mr.Storck 
r. -views the previous attempts tliat have been made, and 
then details his own method, which he claims to be ellect- 
ual, and the principle of which is the diffusion through 
the plantations of eai-bolic acid vapour, injurious to the 
fungus. It is obvious that the success of the plant depends 
upon very many circumstances, which should induce 
cautious experiment on a small scale before embark- 
ing on a large one, such as the depth to which the fun- 
gus penetrates, the state of the weather, the condition of 
the coffee-plant, the influence of the poisonous vapour 
upon it, &e. Should Mr. Storck's experiments prove in other 
hands as successful as according to his statements, sup- 
ported by other testimony before us, they are in his own, 
lie will prove a veritable benefactor, and should receive the 
reward of his public-spirited endeavours to remove a great 
scourge. It is obvious that the principle is applicable 
mutatis mutandis to the treatment of other plants affected 
with superficial moulds. — Ed.] 
My own method of application, says Mr. Storck, is purely 
atmospherical, and for the benefit of the countries and 
planters suffering from the ravages of Hemileia vastatrix 
I will now give a description of it. In doing this I rely, 
as regards my rights of priority and proprietorship in an 
invention of great importance, upon that spirit of justice 
and fair play so generally obtaining in the scientific and 
planting world. 
An acre of coffee land contains thirty-six centres of vapori- 
sation formed by tin vessels to be mounted upon short sticks, 
and covered in a peculiar manner, to protect the contents 
from rain and rubbish, thereby preventing waste and un- 
desirable dilution by rain of the fluid contents of the vessel. 
They consist of a mixture of carbolic acid and water in the 
proportion of from 3 to 10 per cent, of Calvert's best No. 5 
acid, at the option of the operator. Any strength not ex- 
ceeding 25 percent, may be used, since nothing t aches the 
plants or the soil, nor iujures the tenderest young leaf or 
flower-bud. In startiug the treatment I would recommend a 
first charge of In per cent, (5 per cent, is sufficient), and 
then a weekly supply of a density of 5 per cent,, which will 
keep the strength of the fluid up to 3 per cent, for many 
months. An average labourer can in this manner attend 
to at least 50 acres per week. The first season's outlay per 
acre, including the first establishment of the system over an 
estate, will not reach £2 10s. per acre, and for any subse- 
quent year it will not exceed CI. The present model of the 
vessel has an evaporating surface 
contemplating an improvement in it 
gulate evaporation, and "do 'i way with weekly supplies, while 
a farther reduction in the item of labour will be effected. 
The vessels, holding rather over half a pint, can be manu- 
factured wholesale at 4d. each, and are so modelled as to 
allow of the closest packing, the two parts separately ; they 
will last for many years. 
After eleven months of immunity from leaf disease enjoyed 
by the trees treated and cured by me, and of a new nursery 
Thad made in the meantime, a gang of labourers from the 
Upper Hewn carried infection back to the place. Among the 
subjects infected were two Liberian coffee trees, one among 
a cluster of live, and another some short distance off in a 
small plantation of forty, all just in full spike, and to my 
dismay I also found the nursery badly infected. As soon as 
I could ( ;et the materials I started my system of vaporisa- 
tion (July Ith lust). The two Liberian trees I simply fur- 
nished with a small bottle each, partly filled with my mix- 
ture of only 3 per cent., hung into the angle of the lowest 
branches. Loth trees have now been perfect ly free of the 
fungus for some weeks, and not a single one of their close 
neighbours has been infected. They prove to have- been 
complet.-lv isolated by the treatment, not a single spore living 
to reach and infect the others, although in some instances 
almost touching. With the nursery, covering about three- 
quarters of an acre, 1 proceeded in the following manner: — 
Judging that with so small mi area as the above I sh. uM 
be working at a disadvantage through tie- gas escaping 
beyond the limit s of tin- area ami going to waste in every 
direction, I arranged my centres of vaporisation n little 
closer than would be necessary on a large field, and put tin m 
8 yards apart each way. Tin- receptacles of the llui-1 and 
their covers were represented by ordinary rims and saucers, 
pruning thu nips slightly into the ground and uiouutiug the 
iches, but I 
will better 
inverted saucers upon three; or four short ."ticks stuck closely 
round the rim of the cups, I left a clear space of about 1 
inch in depth between the rim of the cup and the cover. 
They were then charged with a dilution of 3 per cent., and 
the effects noticeable alter a few days were most startling. 
old, were fairly recking, began to change colour from the well- 
known bright orange to a dull ochre, until they subse- 
quently turned into dirty yellow and then greyish-white. 
They all, instead of as usual dispersing, remained in a manner 
glued to the leaves, and afterwards dropped with them, 
dead, harmless, incapable of propagation. As time went on, 
all rust which came out began to look dull iu colour and 
sickly, quite different from a healthy crop of spores. By 
degrees pale rings round the rust patches began to show, 
indicating the circumference of the mycelia and where 
their farther development had been arrested. In the third 
month a large proportion of the spots appeared pale green, 
whitish round the edges, and as if drying up in the middle; 
some pushed out a few sickly spores, but very frequently 
none at all. The spots turned into dry tissue, and most of 
those leaves, unless too severely attached, remained on the 
trees. Thenceforth a little dirty-looking rust still continued 
to appear, but the presence of the disease, up to its com- 
plete disappearance, was chiefly indicated by dead and dy- 
ing mycelia. From what I have witnessed, bare contact 
with the vapourised atmosphere seems, if not immediately 
to kill the spores.to effectually incapacitate them from germi- 
nation. From moving round in the nursery, examining the 
effects of the treatment, as I frequently did, I would often 
go in among healthy trees, handle their leaves, pull suckers 
and the like, but not a single instance of further infection 
took place among those trees, Liberian and Arabian, which 
were healthy when the process was started. With grown 
trees, having leaves of denser texture and more uniform 
age than nursery plants, which are almost always grow- 
ing, the effects, although apparently slower at the begin- 
ning, are in the end still more pronounced. They lose 
a greater proportion of leaves atthe start, butall disease upon 
them and in them is dead before the fall, at once neutralising 
a fruitful source of re-infection. In the case of fairly 
vigorous trees a new coat of clean foliage, never again to 
be soiled by the devastating parasite, will have formed by 
My method of permanent vaporisation is specially adapted 
for a country like Ceylon, for instance, where self-sown 
coffee in the forest and native garden patches present a 
standing menace of re-infection, which will defy any other 
treatment. With the permanent atmospherical treatment 
1 have asserte.l elsew here — " Any one employing my pro- 
cess will reap the full benefit of his outlay, even though 
his neighbour's field next adjoining or just across the road 
may be reeking with disease for want of treatment. Js'o 
live spore can be carried out of the area under treatment 
— nothing carried in can live, and re-infection becomes 
impossible." 
For the guidance of any planters who may wish to give 
my system a trial, I will here give the following direc- 
tions :— Before my treatment comes into general use, so as 
to induce the wholesale manufacture of the specified tin 
vessel, planters will have to make shift as I did, with 
cups and saucers, which must be so placed that they will 
not be overturned or buried by stormwater comiug "down 
the hillside, which contingency is avoided with the tin- 
vessel mounted on a stick. Presuming tin- distance be- 
tween the rows and in the rows of coffee trees to be as 
usual (6 feet), commence at the corner of the fields, say 
workiug from right to left, start with the third tree iu 
third row, then follow the base line, placing a vessel iu 
every sixth row between the third and fourth tn e. w hen 
the "base line is thus marked olT. start at right angles 
along the rows, count six and place your vessels between 
the sixth and seventh trewi in a line with tin trees, so 
as not to obstruct work and passage; put down yourcup*, 
drive three to four short |M-gs immediately round the cups 
SO as to steady them, and let the invert ed saucer rest on 
the top of the pegs. They must he of even hnj.t und 
long enough to allow the sjMuit f a wateiing |>ot orotln-r 
feeding vessel to pass through under the roof to saw the 
trouble of lifting it every time— but they should not be so 
