220 ADVANTAGES PRESENTED BY ELECTRO-MAGNETIC MACHINES. 
27. Mn. SCANLAN EXHIBITED A 
BEAUTIFUL SPECIMEN OF HEMA- 
TINE CRYSI'ALLIZED IN THE 
CENTRE OF A MASS OF LOG- 
WOOD . — Records of General Science, 1835. 
PHILOSOPHICAL TRANSACTIONS OF 
THE ROYAL SOCIETY OF LONDON, 
FOR 1835. PART I. 
PHYSICS. 
NOTE ON THE ELECTRICAL RELA- 
TIONS OF CERTAIN METALS AND 
METALLIFEROUS MINERALS. BY R. 
W. FOX. 
The author states that the crystalliz- 
ed gray oxide of manganese holds the 
highest place in the electro -negative scale 
of any substance examined, when it is im- 
mersed in various acid and alkaline solutions ; 
and the other metals and minerals rank af- 
ter it in the following order: manganese, 
rhodium, loadstone, platinum, arsenical 
pyrites, plumbago, iron pyrites, arsenical 
cobalt, copper pyrites, purple copper, galena, 
standard gold, vitreous copper, silver, copper, 
pan brass, sheet iron. When employed in 
voltaic combination he found that on being 
so arranged as to act in opposition to one 
another, the direction of the resultant of 
their action, as indicated by the deflection 
of the magnetic needle, did not coincide with 
the mean of the direction of the needle when 
under the separate influence of each. He 
concludes, therefore, that the needle does not 
indicate the whole of the electricity trans- 
mitted, and that electro-magnetic action does 
not depend upon a continuous electric cur- 
rent, but is better explained on the hypothesis 
of pulsations, formerly advanced by him. 
EXPERIMENTAL RESEARCHES ON 
ELECTRICITY, NINTH SERIES. BY 
MICHAEL FARADAY, D.C.L. &c. 
The inquiry which produced the develop- 
ment of the facts contained in this paper arose 
from the observation of Mr. Jenkin, that, 
if an ordinary short wire be employed to form 
a communication between the two plates of 
an electrometer consisting of a single pair of 
metals, it is impossible to procure an electric 
shock, but if the wire which surrounds an elec- 
tro-magnet be used, a shock is experienced 
whenever the contact with the electrometer 
ceases, if the extremities of the wires are 
held in the hand, while a brilliant spark ap- 
pears at the point of disjunction. In the 
prosecution of his researches the author em- 
ployed the conducting wire in four different 
modified forms: 1st, as the helix of an elec- 
tro-magnet, consisting of a cylindrical bar 
of soft iron, 25 inches long and inch in 
diameter, bent into a ring, which was solder- 
ed to a copper rod which served as a conduc- 
ting continuation of the wire: 2nd, as an 
ordinary helix formed of a copper wire coiled 
round a pasteboard tube, the convolutions 
being separated by a string, and the super- 
posed helices prevented from touching by 
intervening calico : 3rd, as a long extended 
wire, and 4th, as a short wire. Of all these 
forms, the brightest spark and most powerful 
shock are procured by inserting a cylinder 
of soft iron within the helix, so as to form 
an electro-magnet. He found, also, that if 
a current be established in a wire, and 
another wire forming a complete current 
be placed parallel to the first, at the mo- 
ment the current in the first is stopped, it 
induces a current in the same direction in 
the second, the first exhibiting then but a 
feeble spark; but, if the second wire be re- 
moved, a current is induced in the first wire 
in the same direction, and a spai’k elicited 
when the contact is broken. The strong 
sparkinthe singlelong wire or helix, is there- 
fore, the equivalent of the current which is 
induced in a second wire placed parallel and 
in connexion with the first wire. From the 
facility of transferences to neighbouring wires, 
and from effects generally, he considers the 
inductive foi’ces to be lateral, i. e. excited in 
a direction perpendicular to the direction of 
the originating and produced current, and 
they also appear to be accurately represented 
by the magnetic curves, and closely related 
to, if not identical with magnetic forces. All 
experiments tend to shew that the elements 
of the currents do not act upon themselves, 
but excite currents in conducting matter 
which is lateral to them. On using a vol- 
taic battery with fifty pairs of plates the effects 
were exactly similar to those wdth a single 
pair. The author concludes with remarking 
upon the advantages presented by electro- 
magnetic machines, in which the current is 
permitted to move in a complete metallic cir- 
cuit of great length during the first instant 
of its formation, by which means great inten- 
sity is given by induction to the electricity 
which at that moment passes. 
ON THE DETERMINATION OF THE 
TERMS IN THE DISTURBING FUNC- 
TION, OF THE FOURTH ORDER, 
AS REGARDS THE ECCENTRICI- 
TIES AND INCLINATIONS WHICH 
GIVE RISE TO SECULAR INEQUA- 
LITIES. BY J. W. LUBBOCK. 
In the theory of the secular inequalities, 
the terms in the disturbing function of the 
fourth order, as regards the inclinations, 
have hitherto been neglected. As the mag- 
nitude of these terms depends, in a great mea- 
sure, upon certain numerical co-efficients, it 
is impossible to form any precise notion, a 
priori, with respect to their amount, and as to 
the error which may arise from neglecting 
them. The author has, therefore, consider- 
ed it desirable to ascertain their analytical 
expressions. The details of this calculation 
form the subject of this paper. 
ON CERTAIN PECULIARITIES IN 
THE DOUBLE REFRACTION, AND 
ABSORPTION OF LIGHT, EXHI- 
BITED IN THE OXALATE OF 
CHROMIUM AND POTASH. BY SIR 
DAVID BREWSTER. 
This salt occurs in flat irregular six-sided 
prisms, the two broadest faces being inclined 
