42 CALIFORNIA ACADEMY OF SCIENCES. 



CALCULATION OF FORMULA. 



27.175 ^56 = .485 50.99 -=- 70 = .7284 21.835 -=- 18 = 1.213 



The ratios of the lime, anhydrous boracic acid and water are 

 then respectively — 



.485 : .7284 : 1.213, or as 1 : 1.5 : 2.5 as 2 : 3 : 5 



The formula is therefore 2 CaO 3 B 2 3 + 5 H,0, or Ca 2 B 6 O n 

 + 5 H,0. 



Its nearest relations are panderinite 2 CaO 3 B>0 3 -{- 3 H.O 

 and priceite 3 CaO 4 B 2 3 -f- 6 H 2 0. In the ratio of the lime to 

 the anhydrous boracic acid (2 : 3) it is identical with the former 

 and differs from it in the solitary item that it contains two 

 molecules more water than panderrnite. 



A knowledge of this close relationship leads very naturally to 

 the query, Is pandermite an altered or derivative form of cole- 

 manite? 



San Francisco, January 1, 1885. 



JBRARY,! 



