Page:Memoirs of the Geological Survey of Great Britain, Volume 1.djvu/452

Rh AND OnrHBB CONDITIONS OF MATTBK.

439

12. A solutioa of nitrate of silver being put on the glass plate, a globule of mercury was placed, equidistant between either pole. As soon as the crystals of silver (Arbor Dianai) began to form, they radi- ated equally from all parts of the globule, most of them crossing the magnetic lines of force^ although many of them i^proached the axial line ; these did not, however, extend beyond the interior edges of the magnetic poles, and in some experiments there was evidently a tendency to bend ojOT at right angles to the line passing through the two poles at a short distance fitun either. The drawing (Fig. 4) represents the more

Fig. 4.

constant result The interior system of metallic crystals having been formed, lines, which might at first be mistaken lor true magnetic curves of crystals of a sub-nitrate of mercury, began to spread. Although two curved lines of crystals, extending from one pole to the other, gradually settled, yet it was found on close examination that these con- sisted of a great number of minute curves formed simultaneously around the centre of influence, but all of them tending to diverge from the line passing equatorially across the mercury, or the line of equilibrium between the two poles ; and, assuming that order of arrangement, which, after Dr. Faraday, we call diamagnetic. Although a slight formation of crystals marked on the glass the circumference of the iron of the magnet, not a angle crystal was found upon any part over the poles.

13. By pladng equal weights of mercury vpon the poles, tiie plate being filled with a solution of nitrate of ^ver, we get m(Mre distinct evidence of the diamagnetic arrangement. A globule of mercuiy being carefully placed in the centre of the space corresponding to the mag- netic poles, it exhibits a tendency to move oJOT in a curve of the repulsive order ; but by moistening the plate with a little of the silver solution, the globule is rendered stationary. If the plate be now filled up with the solution of silver, there commences, almost immediately, the forma^ tion of crystals of metallic silver. These, under ordinary circumstances,

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