Miscellanies. 193 
Inclination . 13° 13’ 0.92” 
Logarithm of the eccentricity 9.8759106 
Logarithm of half the great axis 0.5486142 
Mean siderial, diurnal motion 533.4409” 
Bib. Univ. Mars, 1833, 
PHYSICS. 
8. New property of elementary electromotors.—Prof. Dal N egro, in 
experiments, to discover some useful application of the magnetism 
communicated to iron by electrical currents, was led to examine into 
the greatest effect which could be obtained from the euales quantity 
of zinc. 
By zinc phites of various sizes, commencing with those of an inch 
surface, and ending with those of one hundred and twenty and one 
hundred and forty square inches, he magnetised a horse-shoe of iron, — 
wound with a spiral. The effects in each case were noted, and 
those of the smallest plates examined by the simple galvanometer. 
From these experiments often repeated, the following results were 
obtained. 
1. Other things being equal, the most useful effect or the greatest 
relative force was obtained from the smallest plate of zinc. Relying 
upon the constancy of this important result, he constructs elementary 
electromotors of plates of zinc, smaller but never larger than one 
square inch. 
2. To obtain from a given plate of zinc the greatest absolute effect, 
divide it into the greatest possible number of parts, and join them 
(par le bas) with copper wire, and arrange them parallel, by tens or 
twenties at pleasure, so as to form a single system, and plunge them 
all at the same instant, into a small copper trough, subdivided into as 
many compartments as there are series of plates, and filled with acid- 
ulous water. 
3. The effect of a given plate of zinc is increased by a pines change 
in figure, of the same surface but of a larger perimeter; e. g- by re- 
ducing a square zinc plate, containing four square inches, to a rec- 
~ tangle of six inches long, and three lines high, the effect is more than 
double 
4, The i increase of the electromotive power depends, for a time, 
upon that of the perimeter, and the division of the constituent parts of 
the most oxidable metal, or, which amounts to the same thing, it de- 
— upon the sum of simultaneous currents, which take place in 
25 
Vou. XXV.—No. 1 
