New Experiments on the Oxygenized Acids and Oxides.'109 
jevel, andthe ball is wantonly thrown down instead of being lowered 
carefully, there can be no injury done. In the course of my own 
experience, I have never met with an instance of the necessity of 
employing a climbing boy to repair the pargetting of a chimney ; 
‘and with respect to the coring-of new chimneys, it reqttires only 
a determination on the part of the bricklayers to avoid the ne- 
cessity of it. 
{t will appear, that the result of my experiments is, ‘that all 
the really. difficult flues to clean, are met with in large mansions 
or public offices, and that the middling and lower classes of houses 
are entirely free from them. The doors introduced in the flues 
ean certainly be constructed to answer, by their locality, all'the 
purposes of convenience, safety, and cleanliness. 
The machines I have seen used are Messrs. Smart’s, Bean’s, 
‘Mumford’s, Skinner’s, Lee’s, and the Bath ; and these are nearly 
the same in principle and effect. 
Smart’s being most used in London, possesses from ‘that cir- 
cumstance advantages the others have not; practice being re- 
quired to give confidence to the men employed. 
The ball for conducting the brush is susceptible of improve- 
ment, inasmuch as making it lighter and larger is found to in- 
-eréase its utility. 
~The machine from Scotland is not yet ascertained to possess 
more advantages than'the others; but that being different in 
‘principle, it may be found capable of improvement. 
I have the honour to be, sir, 
Your most obedient humble servant, 
B.C. Stephenson; Esq. (Signed) Guorce Davis. 
Surveyor General, &c. 
“XVIL, New Experiments on the Oxygenixed Acids and Oxides. 
by M. L. J. THENarD.* 
if HAVE already announced f that muriatic acid, nitric, &c.are sus- 
ceptible of beingsev eral times oxygenated. As it was of importance 
that the quantity of oxygen which they were capable of taking up 
should be determined, 1 have done this with respect to the muria- 
tic acid. 1 took liquid muriatic acid, of such strength that when 
combined with barytes, the solution ‘when slightly evaporated de- 
posited crystals of muriate of barytes, and this acid | saturated 
with deutoxide of barium reduced, by water and trituration, to a 
‘soft paste. By adding the requisite quantity of suiphuric acid I 
precipitated the barytes ; and then treated the oxygenized mu- 
‘tiatic acid-with deutoxide of barium andsulphuric acid, to: oxyge- 
nize it anew ; and in this way charged it with oxygen fifteen times. 
* From Ann. de Chim, et Phys, vol. ix. + See our last number, icp 
or 
