Dr. Heddle's Analysis of the Mineral " Edingtonite." 179 



guage; so much at least as is necessary in order to apprehend 

 the distinction between whatsoever is transitory or accidental in 

 its structure, and whatsoever belongs to its foundations in 

 thought —foundations not less deep, and not less solid, than 



thnsft Ctf wnmetro JfoolP ' 



those of geometry itself. 

 Queen's College, Cork. 



rr\\ 



XXVI. Analysis of the Mineral "Edingtonite." 

 By M. Forster Heddle, M.D., F.R.P.S.* 

 'HE unsatisfactory nature of Dr. Turner's analysis of Edin"-- 

 tonite,— unsatisfactory as to the little insight it affords us 

 into the composition of the mineral, on account of the large loss 

 sustained —has long made it desirable that a second analysis 

 should be undertaken; the extreme rarity of the substance 

 however, has hitherto rendered this impossible. 



Several years ago I was so fortunate as to obtain a specimen 

 of this mineral, and by inducing the dealer from whom it was pro- 

 cured to revisit the locality, several others were found, and I was 

 thus enabled to sacrifice one. I have little to add to the mine- 

 ralogical characters already known. 



The associated minerals are analcime, harmotome in twins calc- 

 spar ruhn-glimmer, green-earth in pseudomorphs after calcite, 

 and cluthalite. 



Specific gravity (determined on 130 grs.) 2'694. 

 Translucent to opake. 

 Colour — white, grayish-white, pink. 

 Powdered mineral absorbs 1-614 per cent, of moisture. 

 Occurs both crystallized! and massivej. 

 On finding that the crystals were invariably associated with 

 harmotome, I was led to suspect the presence of baryta in this 

 mineral, and my conjecture was verified by the qualitative ana- 

 ysis, which showed silica, baryta, alumina, water, and traces of 

 lime and soda. 



The quantitative analysis (made on 25 grs.) afforded, 



Percent. Oxygen. 



Silica . . . 36-98 19-229 21-14 21 



Alumina . . 22-63 10-555 l]-62 12 



Baryta . . . 26-84 2*724 3 3 



Lime . . . trace 

 Soda . . . trace 



Water . . . 12-46 11077 12-12 12 



98-91 

 * Communicated by the Author. 



- New figure*, showing an additional {•ace, will be given in the forth- 

 com>n- " Bntuh Mineralogy " of Meurs. Greg and Lelteom. 

 + One ipecunen in my possession, partly mas*ive, weighs L>i oz 



N 2 * " 



