252 
THE TROPICAL AGRICULTURIST. [October i, 1887. 
lemon and a bit of sugar candy, or balm leaves, 
similarly used, as an infusion; or of lemon grass 
slightly acidulated with citric acid. All these are 
sudorilics, if taken hot, and great quenchers of 
thjrst, too ; they are of immense value in the febrile 
disorders of hot climates, where they act as 
"diuretics." I recommend them all as dog-day 
drinks in Great Britain ; their cost, too, is within 
the reach of a beggar ! As a milk hater, they are 
doubly valuable to me. Ecs. 
[The writer of the above is a pragmatical person who 
believes himself capable of teaching his grandmother. 
Tea is bad because extracts of theine and caffeine 
proved fatal to eats ! Then a country doctor warned 
domestic servants against the evil effects of too much 
tea. Those who indulge in such excess are like those 
who are loved by the gods, — they die young, — witness 
Dr. Johnson. But even the writer benefited by the 
use of green tea when he had overset his brain by 
studying three languages at once! — excess with a 
vengeance. Tea is not prepared as he describes, and 
the best authorities are now agreed that tea is indi- 
genous in India and was introduced thence to China. 
Curious that tea, which to the writer is so objection- 
able, should be recognized as an excellent medicine 
(which it is) in France. The article is a mass of 
contradictions and will not deter any sensible person 
from using tea. — Ed.] 
+. , — 
ON OIL AS A FUEL. 
[The following is the article we alluded to recently 
as worthy of the attention of Ceylon tea planters in 
discussing the question of " the fuel of the future." 
-Ed.] 
V. W. Owston, Cleveland, has issued the following 
upon the subject of oil as fuel, in the form of a circular: 
Inasmuch as the use of oil as a fuel is now engaging 
tl e serious attention of many of our principal engineers 
ai.d manufacturers, we beg leave to submit for your 
c nsideration the following advantages which are claimed 
f^r oil as against coke, coal or wood as a fuel. 
1st. A petroelum fire can be held in perfect control by 
01 e man of ordinary intelligence by the mere turning of 
a valve. He can iucrease or decrease the fire at will, 
, ml can maintain steam or heat at any desired point. 
When the fire is properly regulated to produce the heat 
required,, it can be kept at that point with but slight 
attention, so slight, indeed, that one man can fire and 
care tor a battery of from eight to ten 100 horse-power 
boilers without difficulty. By turning a valve you can 
instantly extinguish the fire, if occasion does not re- 
quire its continuous use, and it can be again started with 
almost, the same rapidity with a few shaviugs or sticks 
of wood. There is no waste, as witli coal, when the 
work is done. 
2nd. The heat generated with petroleum fire is much 
more uniform than that produced with coal or wood. The 
fire is not as stnsitive to the fluctuation of the weather 
as otbei fires. A great advantage is gained in running 
machinery where regularity of speed is desirable. A 
constant supply of steam may be furnished, and there is. 
uo reduction of steam pressure in consequence of the 
replenishing of fires. 
3rd. Economy of Boiling Capacity. — It has been de- 
monstrated that one pound of oil will evaporate the water 
of more than two pounds of coal. The heat units of 
crude petroleum have been erroneously stated to be 
27,531. The fact is that the correct figure, 29,240 heat 
units, has been repeatedly arrived at of late, after many 
tests with Lhe best instruim-nts to be obtained for that 
purpose. In comparing the calorific properties of petro- 
leum it must be borne in mind that with coal there is 
an iK-rmous waste of matter, such as sulphur, slate and 
earthy 8U.0 tances which are practically incombustible, 
and which do not add in the generation of heat. While' 
cM fcheoceticoJIV contains about 14,300 heat Units, that 
ttgur is by reason of tin se impurities reduced to about 
M,000, Puce carbon — charcoal, for instance —contains 
J i,(M)Qbg&t units. Considering, therefore, the impercept- 
ible waste in the burning of oil, and the excessive waste in 
the burning of coal, the conclusion is reached that while 
theoretically the relative proportion of heat evolved 
in the combustion of oil compared with coal is as 20 - 2 
is to 14'3, the proportion practically considered, is in 
favour of oil as 19 is to 8, or 8 - 5 at the furthest. We 
may quite safely assume, then, that the heating cap- 
acity of oil is considerably more than twice that of coal 
as far as now shown. With a clean boiler, properly 
attended, and with the best of coal fuel, well stoked, 
night and day — with every care to insure combustion 
and to avoid waste, the evaporation obtained in some 
isolattd cases specially recorded has been as high as 9h 
pounds. In our every-day experience, however, we find 
that eighty out of a.liundred boilers will not vaporise more 
than from 7 to 7 5 pounds of water per pound of fuel. 
On the other hand, oil tests which, while sufficiently 
conclusive for the present have not by any means 
been carried to the furthest limit, show the vaporiza- 
tion of from 18'24 to 19'5 pounds of water per pound 
of oil consumed, estimating feed water at from 212 deg. 
Fahrenheit. 
4th. Economy in labour, cleanliness and safety are 
secured, as in burning oil complete combustion may 
be obtained. There is no shoveling of ashes, and 
consequently there is a great saving in labour. The 
absence of sparks and cinders and the ability to ex- 
tinguish the fire instantly in case of danger makes it 
very desirable when considered with a view to safety. 
5th. There being no necessity for opening doors 
for the introduction of fuel, there is no fluctuation 
of heat, and no sudden chilling of the flues and 
boiler. The absence of sulphur in the fuel makes its 
action on the metal of the boiler and the flues much 
less destructive than coal, and the flues remain cleaner 
and in better condition to absorb the heat. 
6th. Oil or residuum, is without doubt the coming 
fuel on locomotive and ocean steamers, and by its 
use a great annoyance to passengers in the emission 
of cinders and smoke will not only be entirely avoided 
but less than one-half the room formerly used fo» 
coal will be reqnired to store the oil for fuel, and 
only one-third the weight will be carried, thus saving 
a great deal of room in storage, which will enable 
shipowners to carry an additional quantity of freight, 
or to increase speed to the same amount of power. 
Besides this, where 70 stokers are now required to 
unload coal on ocean steamers, at least GO csiuid 
be dispensed with and the work be done wituout 
the labor of shoveling coal, and the great discomfort 
from heat and dust. 
7th. Regarding the proper construction of furnaces 
for the consumption of oil it may be said that there 
is no occasion for having the combustion cham'ver as 
large as when burning coal. The latter article, being 
solid matter, requires more time for decomposition 
and the elimination of the products and supporters 
of combustion. Coal fuel requires a large fireeham- 
ber and the means for the introduction of air beneath 
the grate-bars to aid combustion. Compared with 
oil the combustion of coal is tardy and requires 
some aid by way of a strong draft. Oil having no 
ash or refuse, when properly burned, requires much 
less spaee for combustion for the reason that, being 
a liquid and the compound of gases that are highly 
inflammable when united in proper proportions, it gives 
off beat with the utmost rapidity, and at the point 
of ignition is all ready for consumption. The changes 
required to burn oil in a coal furnace may be made 
at a nominal cost, so that even in this respect no ad- 
ditional expense is necessary tor a change for the better. 
8th. Three barrels of oil, each of 42 gallons, equal 
and slightly exceed the heating capacity of one ton 
of conl. The oil weighs 913'£ pounds and may be 
purchased and delivered in tank cars at any point in 
the United States at a very low figure. It should be 
remembered that oil need not be shoveled from the 
cars to the furnace, it needs no stoking nor 
poking, it leaves neither cinders nor ashes to 1 e carted 
away and it makes no smoke. With an oil furnace 
one man may attend to n dozen boilers without any 
further assistance. 
9th. The fact of being able to produce with oil a 
perfectly clear white (ire, free from ashes, smoke, dust 
