Chemistry and Physics., 419 
(4.) Pointed armatures and een cial at a distance less attrac- 
tion than cylinders of the same diam 
9.) The attraction of armatures ai magnets gl eatoal diameter in- 
creases “o contact or ata disiance) with their lengths, 
Vith magnets and armatures of equal weight, the cern di- 
minishes more slow wly in proportion as these are shorte te\and thicker. 
(7.) Afier a certain distance armatures of e equal mass are equally 
attracted, 
_ (8.) Magnets of easel weight have an equal attractive force ata 
distance, when, with the same galvanic effect, the spiral surrounds the 
magnet throughout its whole length. 
ith an equal surface of contact, magnets and armatures attract 
equally both when in contact and at a dist nce. 
-) The attraction is proportional to tha square of the number of 
Bide of the electro-magnetic spirals. 
11.) The attractions are proportional - the squares of the mRgng 
izing currents.—(Law of Lenz and Jacob 
(12.) ‘The attraction increases with the He of the whole num- 
ber of spiral windings to the surface of Contes up to a certain limit. 
This nt lies very near the surface of con 
(13.) The attraction increases more her ‘the spiral remains the 
Same and only the iron core is made longer, than when in making the 
core longer the same number of windings i is spread out over the whole 
length of the core. 
(4, ) With the same magnitude of he se Ps the attraction re- 
fat the same at a distance, when it is ame while in contact, 
hatever form the magnet and ices ral hay 
_ (15.) The slings: remains the same when hig diameters of the 
Magnet and armature are interchanged. 
16.) ‘The Biecion remains the same when the armature is made 
the magnet and the magnet the armature, (provided that the spiral, with 
the same galvanic effect, surrounds the iron core throughout its whole 
length, 
(17.) In different systems of eqnal length and equal diameter, the 
maximum attraction takes place when the armature and the magoet are 
of “als ngth.—Pogg. Ann., Ixxx, Ixyxi, 494, 46. 
he Amid compounds of Cyanogen.—Coxrz and Cannizzaro 
have bated the products of the action of gaseous chlorid of oe 
gen upon ammonia. When the chlorid is passed into an ethereal solu- 
- tionof the alkali, chlorid of ammonium is formed and separated, while a 
ey 
°, but sometimes remaining liquid much below that temperature, in 
this case however, it instantly solidifies on being touched with a pointed 
glass rod ;. its 
ts 
rkable phenomenon; the fused mass suddenly Eps with ev: 
of great heat; the new substance thus produc 
