On the Detection of Fluorine. 3 ±9 



billions, but perchance of billions of billions. And what is a 

 billion of billions 1 The number is a quadrillion, and can be 

 easily represented, thus: 1,000,000,000,000,000,000,000,000; 

 and the same schoolboy's calculation may be employed to shew- 

 that to count a quadrillion at the rate of 200 in the minute, would 

 require all the inhabitants of the globe, supposing them to be a 

 thousand millions, to count incessantly for 19,025,875 years, or 

 for more than 3000 times the period for which the human 

 race has been supposed to be in existence. — Professor Low. 



, . 



On two New Processes for the detection of Fluorine when 

 accompanied by Silica ; and on the presence of Fluorine 

 in Granite, Trap, and other Igneous Rocks, and in the 

 Ashes of Recent and Fossil Plants. By George Wil- 

 son MD* 

 \ 



In several communications made to this Society and to the 

 British Association, I have announced the results of a series 

 of observations on the distribution of Fluorine throughout 

 the mineral, vegetable, and animal kingdoms. To myself, 

 the least satisfactory part of these investigations has been 

 the inquiry into the presence of fluorine in plants, for I have 

 been more frequently foiled than successful in my attempts 

 to detect it in them. Others have not, apparently, been 

 more successful. Daubeny was as unable as Sprengel at an 

 earlier period had been, to obtain evidence that the element 

 under notice is present in vegetable structures ; and Will of 

 Giessen, the discoverer of fluorine in plants, speaks only of 

 "traces" of it having been detected in barley. Later ob- 

 servers have not spoken more confidently concerning its 

 abundance in vegetables ; and in the many analyses of the 

 ashes of plants which have recently been published, it sel- 

 dom, if ever, finds a place. 



That one cause of this apparent rarity of fluorine in vege- 

 tables, is the small extent to which it occurs in them is cer- 

 tain ; but I have never doubted that the chief reason why it 

 . 



* Read before the Royal Society of Edinburgh, April 19, 1852. 

 VOL. LIU. NO. CVI. — OCTOBER 1852. 2 A 



