356 © Electro-Magnetic and Magneto-Electric — 
when the acid is suffered to fly off. Nothing remains but the 
brown Jac-stained liquid. 
‘Liquid carbonic acid did not appear to act on any of the metals 
or ‘oxides, but the experiments on this point demand a. further 
examination. Its inaction is probably owing to the * want of the 
force of ‘ presence,’ or of ‘disposing affinity.’ 
“When the liqtiid has been frozen in a tube of lies the tube 
may be melted off by the blow. pipe, and hermetically sealed. 
Such a tube will always retain the liquid, or gas, the former, if 
in sufficient quantity, at all temperatures, if not, the latter alone 
will be found in it at high temperatures. I have one such tube, 
‘which begins to show moisture at 56°, and exhibits a constantly 
elongated cylinder of liquid, as the edldivens i is ie * At 32° 
the cylinder is about half an inch in length. 
Carbonic acid mechanically powerful as it is, is not applieab® 
perhaps, either to locomotion or projection ; but though the rea- 
sons for this are most of them obvious, the Franklin Institute has 
appointed a committee to investigate and report on the subject, 
that the exact truth may be known, and the ‘waste of. time and 
talent eapad otherwise to be —— be =“ to the country. 
Arr. XVI —On a coal Sn Sa and Megwit. 
Electric Formula. . 
Extracted from the Journal of Chemistry, by Erdmann and ee Seidel: and 
forwarded for meena in this Journal. 
Mr. Scuweiccrr repeated on the 26th of. July, 1834,. before 
the Society of Physiciens of Halle, several of the experiments 
which he had already performed in his public lectures in the 
University. He demonstrated by those experiments that a mag- 
net turning around its axis, produces a greater accumulation of 
electricity than a couple of small disks of zine and copper, of 
about the size of a half crown, (or half dollar,) and are wetted 
in a solution of muriate of soda. For whilst the current of this 
hydro-electric combination produced a constant deviation of the 
needle of 30° to 40°, they observed in turning the magnet, in-. 
stantaneous existionie of 160° to 170°, and the magnet being con- 
tinually Gs the needle finally. stopped between 60° and 70°. 
