PHYSICAL SCIENCE. 33 



dinary power which we are now taught to refer to particular 

 conditions of electricity, in its connection with material 

 media. G eneral Sabine, whom the labours of a life have 

 rendered our highest authority on terrestrial magnetism, has 

 recently furnished evidence, from the exact coincidence in 

 time of magnetic changes or disturbances at remote parts of 

 the globe, that these are due to causes from without, irre- 

 spective of local conditions of the earth or atmosphere ; while 

 in pointing out the correspondence of certain periodical 

 variations with the several conditions of the Sun, he has 

 shown a direct magnetic relation between bodies thus distant 

 in space. Diurnal or annual changes, subject to this relation, 

 we may in part comprehend ; but it needs new elements of 

 knowledge to link together in theory, as General Sabine 

 and Schwabe have seemingly done in fact, the maxima and 

 minima of magnetic variation, with the greater or smaller 

 number of dark spots present on the sun's surface ; a coin- 

 cidence expressed, on present proof, by periods of ten to 

 eleven years ; but one so extraordinary in character, that we 

 are bound to await other periodical recurrences before finally 

 admitting it into the records of discovery. 



Meanwhile the Moon also has been found, by delicate 

 observations and averages carefully collected, to exercise a 

 magnetic influence on the earth ; the needle expressing to 

 the human eye certain small variations which strictly corre- 

 spond with the lunar hour angle. This fact has its peculiar 

 interest in suggesting, and with much probability, a similar 

 influence throughout the whole planetary system, and possibly 

 far beyond. The magnetic conditions and changes of the 

 earth itself come into direct testimony here ; so general 

 and strictly coincident over its surface, as to make it certain 

 that the total globe is in a definite magnetic state; and 

 capable through this state of affecting other worlds, as well 



