#. 
488 Essay towards a natural 
and obliging attention, and the interest which you evince for 
the Haytians. 
The precious discovery of vaccination is too important to hu- 
man life, and does too much honour to humanity, not to induce 
‘me to adopt it in my kingdom. On the arrival of Mr, Prince 
Sanders, I put vaccination in use with a view to make it generally 
followed by the Haytian. practitioners ;—we have an innume- 
rable quantity of children to vaccinate. 
It is my intention to give every possible latitude to the happy 
results of this immortal discovery, which I had not hitherto 
been able to put in practice in consequence of the disappoint= 
ament which 1 met with in the applications I made at Jamaica, 
St. Thomas, and in the United States of America, relative to this 
object, the salutary. effects of which I am well acquainted with. 
This benefit will still add to the gratitude of the Haytians for 
the great and magnanimous British nation. 
I have charged Mr. Prince Sanders to testify to you personally 
my sincere thanks, 
<t (Signed) HEwR. 
XCII. Essay towards a natural Classification of simple Bodies. 
By M, AMvEne*, 
Wauer the arbitrary hypotheses which had long led chemists 
astray were banished from science, and it was ascertained that 
we were to consider as simple, all the bodies which had not yet 
been decomposed, the number of these bodies was not two- 
thirds of what they are now: this number successively increased 
as the processes of chemical analysis were applied to compounds 
which had not yet been analysed, or which had been so but im- 
perfectly. Every time that a new simple body was discovered, 
a further term of comparison was obtained, and new relations 
were observed: it became necessary sometimes to restrain, and 
sometimes to generalize, the first views of the fathers of medern 
chemistry ; and the want of arranging simple bodies in an order 
which renders more sensible their. mutual relations, and facilitates 
the study of their properties, beeame more and more felt. ~ This 
order may be purely artificial, like the systematic classifications 
which were at first resorted to in the other branches of the na- 
tural sciences: it may also be deduced from the ensemble of the 
characters of the bodies which we propose to classify ; and by 
constantly uniting those presented by the most numerous and 
essential. analogies, they will be i, SA ATY, what the natural 
methods are to botany and zoolog 
* Annales de Chimie et de Physique, tome i. p. 295. March 1816. 
Hitherto 
