1822.] 
at the wrist to improve in tonic character 
as it lessens in irritative celerity.. A proof 
positive of the. principle contended for, a 
demonstration actual that fox-glove is not 
only then an agent of efficacy, when it is 
Report of Chemistry and Experimental Philosophy. 
459 
so administered as to occasion a sudden 
and conspicuous diminution in the force 
and frequency of arterial. movements. 
D. Uwins, M.D. 
Bedford Row, May 20th, 1822. 
REPORT OF CHEMISTRY AND EXPERIMENTAL PHILOSOPHY, 
—=—_ 
LETTER on the IMPROVEMENTS in the 
COPPER WORKS al SWANSEA. 
b Giese perusing the 367th No. of your 
valuable Miscellany, I observed, inthe 
Report of Chemistry and Natural Piiloso- 
phy, the result of an experiment, men- 
tioned as having. been tried at Cadoxton 
near Swansea in Glamorganshire, which 
has proved successful in the removal of the 
pernicious effects arising from the smelting 
and ealcining of copper ores. Your in- 
sertion of the following extract of a letter, 
which I had the honour of submitting on 
the 9th of Jan. last to the committee of 
gentlemen at Swansea appointed to re- 
ceive plans for the effectual removal of the 
pernicious effects of the copper smoke, 
which have been so severely felt in that 
neighbourhood, will be esteemed a parti- 
eular favour. ‘‘ Having endeayoured to 
shew that these particles of matter are of 
a metallic nature, and, capable of reduc- 
tion to their original state, are of much 
greater density than atmospheric air ; 
allow me to account for their being car- 
ried off by it; and then to submit that part 
of my plan which regards their collection 
and preseryation, to you for your judgment, 
I propose that, instead of the chimney 
being erected upon the present plan, thus— 
3 
that it be built nearly in an horizontal line 
with the furnace, thuse= 
so that it be of a gradual elevation to- 
wards the extremity ; in which position, it 
will.be found to have-all the requisite pro- 
perties of a chimney-erected upon the old 
plan, while, ic opposes an insurmountable 
impediment to the rise of the heavier par- 
ticles of metallic matter which escape from 
the furnace, impeding. their velocity by 
perpeteniy presenting a’ rough surface; 
with which they willmnavoidably come in 
contact; for the rarefied air, &c. which has 
always a tendency to ascend, does not, as 
in the upright chimney, find a)free .pas- 
sage, but will be obliged to steal along (if I 
may be allowed to use such an expression) 
the upper part of the chimney, by which 
means the heavier particles are thrown 
back by striking against it, and retained in 
the battom, where the current (if there be 
any) is not of snfficient strength to carry 
them on, while the bituminous and sulphu- 
rous smokes are carried off as freely as can, 
possibly be required. As it regards what 
T have been saying, I must beg leave, my 
lords and gentlemen, to observe, I have nat 
been reasoning upon mere hypothesis, but 
upon an absolute knowledge of the fact, 
that the metallic particles will be re-- 
tained in the manner I have deseribed 
above, and that the draught of the chimney 
will be equal to one erected upon the old’ 
plan.” 5 
From the above, I conceive it will be. 
evident that the principle adopted, and the 
principle of the above plan, are the same ; 
but how far it was entitled to any notice 
from the committee alluded to at the com- 
mencement of my letter, I shall leave for 
you and your readers to determine, as 
nothing is farther from my wishes than to 
detract from the just merits of others; but, 
since the name of no individual has yet ap- 
peared, and no notice has been taken of. 
the above by the committee, I conceive 
I should not be doing myself justice were 
Tnot tolay this statement before the pabhe, 
At the close of my Jetter to the committee, 
I observed, that, should this part of my 
plan meet their approbation, J should feel a 
pleasure in forwarding them the remainder 
for the complete eradication of the whole 
evil by condensation, which, shauld it meet _ 
your approbation, I shall feel a pleasure in_ 
offering to the public through the medium _ 
of your next publication, STE 
E. W. Rupper. 
Frederick Place, Birmingham; May 17. 
Proressor HANsTEEN, of Christiana, - 
has -published the following obser'vatious - 
on magnetism :— M3 lizanccets: 
With a little oscillatory instrument, 
consisting of a magnetized steel cylin- - 
der; suspended by, a very fine silk thread, 
and:inclosed in a glazed case, I observed, 
(says he), at Christiana, in the months of 
November and December 1819, and. in- 
Mareh, Apvil, and May 1820, seven or- 
eight times every day, the time of 300. os- 
cillations, by which Lhave found— 
First ; that the magnetic intensity of the 
earth is subject, to a diurnal variation, so 
that it decreases from the first hours of 
morning 
