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XXIV. On the composition of chloride of barium. By Dr. Edward Turner, 
Professor of Chemistry in the University of London. Communicated by Dr. 
Dionysius Lardner, Fellow of the Royal Society. 
Read May 14, 1829. 
In tai dng a review of the present state of chemistry ; — of the numerous com- 
pounds that have been discovered within a very limited period, and of which 
many have as yet been but partially or imperfectly examined ; — of the results, 
often discordant, which analysts have obtained ; — and of the opposite theoretic 
views which are prevalent, — it is difficult to avoid suspecting the propriety of 
opinions that have been thought to rest on the sure basis of correct observa- 
tion, or doubting the accuracy of analyses conducted by chemists of the highest 
reputation. The era of brilliant discovery in chemistry appears to have termi- 
nated for the present. The time is arrived for reviewing our stock of infor- 
mation, and submitting the principal facts and fundamental doctrines of the 
science to the severest scrutiny. The activity of chemists should now, I con- 
ceive, be especially employed, not so much in searching for new compounds or 
new elements, as in examining those already discovered ; in ascertaining with 
the greatest possible care the exact ratio in which the elements of compounds 
are united ; in correcting the erroneous statements to which inaccurate obser- 
vation has given rise ; and exposing the fallacy of opinions which partial ex- 
perience or false facts have produced. Considerable as is the labour and dif- 
ficulty of such researches, they will eventually prove of great importance to 
chemical science by supplying correct materials for reasoning ; and will some- 
times, even in the most familiar parts of analytical chemistry, lead to the de- 
tection of errors that had escaped notice, and which vitiate many analyses pre- 
viously regarded without suspicion. An instance of this kind I shall have 
occasion to notice in the present communication. 
The foregoing reflections have been more immediately elicited by circum- 
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