On the magnetic characters and relations of oxygen and nitrogen / Professor Faraday.

  • Faraday, Michael, 1791-1867.
Date:
1851
Catalogue details

Licence: Public Domain Mark

Credit: On the magnetic characters and relations of oxygen and nitrogen / Professor Faraday. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    scribed as the centre of magnetic force,) a glass tube drawn to a point (as in the apparatus used for blowing the delicate soap-bubbles,) and filled with water ; by slowly withdrawing the water, the air could be drawn into the tube from any desired spot and tested. This was done; and it was found that even when the magnetic action was most intense, the proportions of the magnetic oxygen and of the non- magnetic nitrogen were undisturbed.—The following experiment proved that no condensation was produced on oxygen by the magne- tic power, i. e. that it is not aggregated, as happens with iron filings when under the influence of the magnet. The flat-faced poles of the magnet were separated the 60th of an inch by a copper plate with an aperture in the middle, so that when the whole was clamped together a chamber was formed. By gauges attached to this chamber it was found that no trace of condensation occurred, however great was the magnetical force brought to bear on the oxygen. The loss of magnetical power occasioned by heat was then noticed. This was shown first in the case of iron heated to redness ; then in that of nickel raised to the temperature of boiling oil; and lastly, in the case of the air (i. e. of the oxygen in this air) by the following experiment: — Two conical poles a little separated were employed ; above was placed a piece of phosphorus on paper, and below a helix of platinum wire heated to redness by a small Grove’s battery independent of that used to excite the electro-magnet. The heated air, rising upwards from the helix, speedily inflamed the phosphorus above it whilst the electro-magnet was unexcited ; but when rendered active, the oxygen in the heated air becoming less magnetic, was dis- placed by the current of colder (and consequently more magnetical) oxygen, and the phosphorus in consequence remained unaffected by the mass which glowed beneath it, until the electro-magnet was deprived of its power; and then the natural laws of specific gravity came again into operation, the heated air rose, and the phosphorus was lighted. In conclusion, Mr. Faraday announced his intention of applying, on a future evening, the reasoning deducible from these and other experi- ments, to the variation of magnetic lines on the earth’s surface. His purpose then will be to compare the records of this varying force with the variations of temperature occasioned by the annual revolution of the earth, the varying pressure of the atmosphere, storms, &c. with the hope of supplying a true theory of the cause of the annual and diurnal, and many of the irregular variations of the terrestrial mag- netic power. For the papers in which these results are described more at large, see Philosophical Magazine, 1847, Vol. xxxi. p. 401 ; and Philoso- phical Transactions for 1851, p. 1. Among the objects exhibited in the Library, were—a water-worn Lump of Gold, (weight 219 oz. 8 dwt. 12 gr.; value about £826,) from Carson’s creek, California [by the Governor of the Bank of B 2