850 
Supplement to the "Tropical Agriculturist" [June 1, 1895. 
I may here mention that in writing down the 
chemical formula, I hare adopted what is known 
as the rational or constitutional method, by 
which not merely the composition but also the 
constitution of substances is shown. For instance, 
lliu empirical or ordinary method of writing the 
chemical formula of carbonate of lime is 
CuCOa — this shows us the composition of the 
substance. But by giving the formula us Ca O, 
CO2, we denote in addition to the fact that 
carbonate of lime consists of the elements calcium, 
carbon and oxygen in certain proportions, the 
relation of these elements to each other, — calcium 
and part of the oxygen existing in combination 
ns quick lime, carbon and the rest of the oxygen 
existing as carbonic acid gas. We are able to 
make this statement because we know that when 
carbonate of lime decomposes under the action 
of heat it is resolved into quick lime and car- 
bonic acid gas. Rational or constitutional for- 
mula are, therefore, to be preferred in many 
respects to empirical formula, since, to adopt 
a simile, they do not merely tell us the indivi- 
duals of which the household is composed, but 
the relation of those individuals to each other. 
But to return to our subject proper — given quick 
lime and carbonic acid gas, we can in this way 
prepare carbonate of lime, synthetically that is 
from its constituents. But what is of more 
importance to us, we can, by heating carbonate 
of lime, resolve it into its constituents, viz., quick 
lime and carbonic acid gas. This then is the 
process that goes not in the lime-kilns, and which 
is known as lime-burniiiy, though it is carbonate 
of lime that is so burnt and yields quick lime 
which is left in the kiln, and carbonic acid gas 
which escapes into the atmosphere. The decom- 
position, by heat, of carbonate of lime may be ■ 
thus expressed by a chemical equation: — 
Ca O, CO2 = Ca O + CO2 . 
One hundred paits by weight of carbonate of lime, 
yielding 06 parts of quicks, the carbonic acid 
gas escaping into the atmosphere. This carbonic 
acid gas (which we shall see later on, plays an 
important part in the setting of mortar) is the 
same substance that is found in the exhaled 
breath of all animals, and is found existing to 
the extent of about 4 parts in every 10,000 of 
air. There is a simple test for carbonate of 
lime, viz., the application of a few drops 
of hydrochloric acid, which is followed by an 
effervescence or bubbling up, due to the escape 
of carbonic acid gas, which, as we have seen, in 
combination with quick lime forms calcium car- 
bonate. The action of hydrochloric acid on car- 
bonate of lime results in the formation of 
chloride of lime and water, with the escape of 
carbonic acid gas. The reaction is chemically 
expressed by the following equation : — 
Ca O, Cl 2 + 2 HC=CaCh + H 2 O + CI2 . 
Carbonate of lime and hydrochloric acid, forming 
calcium chloride, water and carbonic acid gas. 
This test is often a useful one, for there are 
some forms of carbonate of lime which are 
difficult to distinguish from other substaces similar 
in appearance, but totally different in composition, 
$uch as gypsum, milky-quartz, kaolin, and talc. 
(2b be continued.) 
VETERINARY LECTURES FOR THE PEOPLE. 
In a late number of t Ik- SeattM Former an ex- 
cellent suggestion is made by a correspondent 
who recommends t lint "the agricultural section 
of the Technical College, or any other body, should 
arrange for a series of lectures on Veterinary Sur- 
gery to be given. Of course, this would not I* at 
all in t he way of qualifying far any degree, but 
simply to take the place towards the brute creu- 
tion that ambulance or first-aid does towards man. 
It is notorious the amount of preventable suffering 
endured by animals, owing to those in charge not 
having the slightest knowledge of even the sim- 
plest causes or remedies. I am certain such lec- 
tures would be largely attended by those keeping 
animals either for pleasure or profit." 
In reading the above it immediately struck us 
that the suggestion could be modified and adopted 
with much advantage in Ceylon. We have here a 
Colonial Veterinary Surgeon, whose duties are by 
no means overburdensome, and consist of holding 
three classes (each of 4o minutes' duration) a week 
at the School of Agriculture, und visiting areas 
infected with cattle disease whenever necessary 
During the greater part of the yeur, however, thnre 
is seldom a call upon the Veterinary Surgeon 
to visit the Provinces, while for three month- in 
the year there is no teaching work to be done in 
connection with the School of Agriculture. 
Bow then could a fully-qualified Veterinary 
Surgeon, who has had a distinguished career in 
College, wish to be better employed than in making 
a tour of the Provinces, scattering a knowledge of 
veterinary surgery (on "first aid" principles) as 
suggested by the correspondent whom we have 
already quoted. It may be assumed that the 
subordinate revenue officers in the Provinces have 
a sufficient knowledge of English to understand 
and appreciate lectures 6uch as would be delivered 
(that is, lectures of a practical nature free from 
technical verbiage) by the Veterinary Surgeon in 
the chief town or towns. 
If this suggestion is impracticable, we have 
another Veterinary Officer available in the person 
of Mr. W. A. deSilva. who with his Indian train- 
ing (under conditions very similar 10 those which 
obtain in this country), his local experience, and 
his partially for the use of accessible and inexpen- 
sive (and not less efficacious for that! drugs which 
have made bis remedies so acceptable to the 
natives, «ill ''ruble (o address Sinhalese audiences 
in their native 1r,y>gue, and give them such nd\ ice 
as will be invaluable to them in their present help- 
less ignorance. 
In referring to the suggestions of the correspon- 
dent quoted above, the Scottish Farmer (in its 
" Current Topics' column) remarks that " the pro- 
posal is deserving of serious consideration," adding 
further : " The proposal is not to make every man 
his own Veterinary Surgeon ; the ambulance 
classes have not made every man his own doctor; 
and while a little knowledge is a dangerous thing 
when possessed alone and exercised with presump- 
tion, it is a very valuable thing in its own place." 
We fully endorse the opinion herein expressed, 
and are confident that in the direction we have 
indicated there is an opportunity which should 
not be lost of utilising the services of our Veterin- 
ary officers to advantage. 
