4
E. M. CLARKE S ACCOUNT OF A SERIES OF EXPERIMENTS, ETC.
Note read 2nd October, 1838.
I have already stated in the preceding paper, that in experimenting with the large Magneto- Electrical Machine, I obtained the greatest evolution of gas, from points, when the Intensity inductor was employed, and from plates when the Quantity inductor was employed. On repeating these experiments at the Polytechnic Institution, in the presence of Sir George Cayley, I was induced to compare the effects of the inductors, when both points and plates were used in connexion, that is to say, I connected a voltameter, fitted with points, to one fitted with plates, and placed them in the Magneto-Electrical Circuit, first with the Intensity inductor, and then with the Quantity inductor, and found that with the Intensity inductor, when the points and plates were in connexion, I had increased effects from both, the delivery of gas being still the greatest at the points; but with the Quantity inductor, the points and plates remaining in connexion, diminished effects were obtained from both; the diminution, however, being infinitely greater at the points.
These distinctions were so considerable as to be obvious to the eye, and Sir George Cayley expressed perfect satisfaction as to the results, but afterwards I thought it advisable to repeat the experiments, and note them more minutely. The results obtained are arranged in the following Table : —
TIME IN EVOLVING A CUBIC
INCH OF THE MIXED GASES.
Intensity Inductor.
Quantity Inductor.
From points 16' 40" From plates 6h. 40'
From points 5' 33" From plates 1' 42"
Connected.
Connected.
From points 14' 26" From plates 3h. 20'
From points 14' 26" From plates 6h. 40'
The general result, therefore, is, that the points with the Intensity inductor, and the plates with the Quantity inductor, produce the greatest effects; the latter arrangement being the more efficient of the two, while points and plates are unconnected; but that when these are in connexion, the points are rendered more efficient with the Intensity inductor, and less efficient with the Quantity inductor, their influence being in fact so modified as to be equally efficient with either inductor: but the efficiency of the plates, while it is doubled with the Intensity inductor, is so reduced with the Quantity inductor, as to be only equal to their inefficiency with the Intensity inductor when out of connexion with the points.
E. M. C.
Lowther Arcade, London.