248 THE INTELLECTUAL RISE IN ELECTRICITY. 



manufacture of printing-ink and of incense; when burned 

 it was supposed to be a sure preventive of plague and as 

 that terrible scourge then ravaged Europe almost un- 

 checked, the demand for the resin was great. It was 

 carved into rings, beads for rosaries, and statuettes. But, 

 next to its employment for fumigation, its most extensive 

 use was as a specific for checking hemorrhage, nausea and 

 catarrh. Thus it found its way chiefly into the hands of 

 the physicians, and thus it doubtless came to pass that to 

 the members of the faculty were owing the remarkable 

 discoveries which had their basis in its attractive property. 



Agricola, however, perceives no difference between its 

 attraction and that of the magnet. He enumerates down, 

 chaff, hairs, leaves and other small things including even 

 metal filings as drawn to it, the last probably fortifying 

 him in his individual belief in the similarity between it 

 and the lodestone. Yet he notes that, when rubbed even 

 with the finger, it becomes hot, and still hotter when the 

 friction is applied with a coarse cloth, or even with a hard 

 substance; but one's faith in his accuracy is somewhat 

 rudely shaken by his culminating assertion that there is 

 found on the shores of the Vistula a grey amber which, 

 on being rubbed with iron, will cause leaves lying on the 

 ground to fly up to it, even if held a distance of two feet 

 above them. 



Cardan transcribes, almost literally, Agricola's list of 

 things which the amber will attract, and then, for the first 

 time, offers an interpretation purely physical. He specu- 

 lates neither upon similitudes, sympathies or analogous 

 principles, but boldly assigns a wholly material cause; 

 namely, "that it has a fatty and glutinous humor which, 

 being emitted, the dry object desiring to absorb it is 

 moved toward the source, that is the amber. For every 

 dry thing, as soon as it begins to absorb moisture, is 

 moved toward the moist source, like fire to its pasture; 

 and since the amber is strongly rubbed, it draws the more 

 because of its heat." It is not necessary to criticise this 



