116 ANNUAL OF SCIENTIFIC DISCOVERY. 



regions of the opposite hemisphere. Continuing on towards the north 

 pole from the south-west, they enter the arctic regions, on a spiral 

 curve, continually lessening the gyrations, until, whirling about in a 

 contrary direction to the hands of a watch, this air ascends and com- 

 mences its return as an upper current, to the belt of calms at the 

 tropic of Cancer. 



Lieut. Maury attributes to magnetism that influence or power " which 



f aides the ah* from the south through the calms of Capricorn, of the 

 quator, and of Cancer, and conducts it into the north," and back 

 again. This he compares to a spiral coil, and the continuous circuit 

 of a magnetic current passing around both poles and winding across 

 our globe. The attractive and repulsive influence is attributed to the 

 nature of oxy.gen, which, as its temperature is increasea, diminishes in 

 para-magnetic force, and which increases as its tempera ture falls. 

 The whole subject, which is of great interest, is to such an extent 

 complex, that a partial abstract like the foregoing does not afford a full 

 illustration of Lieut. Maury 's views or arguments. 



ON THE CONNECTION BETWEEN THE COLOR OF SUBSTANCES AND THEIR 



MAGNETIC PROPERTIES. 



MR. RICHARD ADIE, of Liverpool, communicates to the Edinburgh 

 Philosophical Journal, April, the results of an investigation, under- 

 taken with a view of ascertaining whether there was any connection 

 between the color of a body and its magnetic properties. The exper- 

 imental tests for magnetism, in the various bodies examined, were made 

 partially by means of the torsion balance, which takes cognizance of 

 degrees of _ magnetism long before a magnet will show any attraction 

 when applied in the usual way ; and partially by spreading the pulver- 

 ized substance over a smooth sheet of paper, when, if the substance 

 was strongly magnetic on the torsion balance, an ordinary steel mag- 

 net, moved to and fro close beneath the paper, without touching, will 

 set some of the particles in motion. The result of Mr. Adie's experi- 

 ments seems to show that when the forces of aggregation which bind 

 the particles of a substance together produce transparency, or white- 

 ness, such a combination has feeble magnetic properties ; and that 

 when the same forces produce a dark, or dull-colored substance, then 

 the magnetic power is more developed. This relation between color 

 and magnetic attractions of bodies must be held to rest only among 

 those of similar constitution. 



Among the numerous illustrations, confirmatory of the theory 

 brought forward by Mr. Adie, we select the following : The ferro- 

 cyanide of potassium is a translucent lemon-colored salt, possessed of 

 no attraction for the magnet ; when heated moderately, it loses water 

 and assumes an opaque white hue, but is still unattracted by the mag- 

 net ; when the heating is continued until the color darkens, then the 

 degree of darkness becomes an index of the magnetic force, until the 

 color reaches black, when the altered salt has all the characters of an 

 iron body. If this was a solitary case the change would at once be 

 set down to the decomposition of cyanogen, and the formation of a 

 carburet of iron. 



