330 Dr Charles T. Jackson on 



that burned or ground bones may be used for the same pur- 

 pose as the mineral I am about to describe ; nor will it be 

 necessary to enter upon the discussion of the question as to 

 the indispensable necessity of the existence of phosphates in 

 food, which is to form flesh, blood, and bones, for most men 

 know that they have seven pounds of phosphate of lime in 

 their bones, and nearly as much of other phosphates in the 

 soft parts of their bodies. It is also known that the ashes 

 of all cereal grains contain almost fifty per cent, of phospho- 

 ric acid, united with lime, potash, soda, and magnesia, and that 

 plants derive their phosphates from the soil, which contains 

 generally but a very minute proportion, rarely amounting to 

 three-tenths per cent. 



Description and Analysis. 



This mineral was first described by Professor E. Emmons, 

 in his report on the geology of New York, and was analyzed 

 by Professor Lewis C. Beck, and published in his report on 

 the mineralogy of New York, p. 240 ; but his specimens dif- 

 fer somewhat from mine in their physical characters. It 

 was named Eupyrchroite by Professor Emmons in allusion to 

 the beautiful emerald green light which it gives out when 

 thrown on heated iron, its phosphorescence being nearly 

 equal to the chlorophane fluor spar of Connecticut. 



Tihe Eupyrchroite phosphorite occurs in botryoidal concre- 

 tions having a fibrous structure, and an ash gray or bluish gray 

 colour, the concretions being made up of successive layers of 

 different shades of colour. Their surface is frequently covered 

 with a delicate film of iron pyrites which scales off* readily 

 when scraped with the knife. Its specific gravity is 3*053 ; 

 Hardness 4^^. Before the blowpipe phosphoresces with a 

 green light at first, then gives the intense brightness cha- 

 racteristic of lime salts. It glazes on the surface at a high 

 temperature, but does not melt. In the glass tube it gives 

 out water, which is acid, and corrodes the glass. When 

 thrown in powder on metal heated nearly to redness, it ex- 

 hibits a brilliant emerald green phosphorescence. Large 

 fragments decripitate strongly. 



During its solution in chlorohydric or nitric acid, it effer- 



