88 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
Of this altered chloropheite, 1 +003 grammes yielded—- 
Silica, . F ‘ 7d 
From Alumina, . ‘007 
“178 = 17° 746 
Alumina, . ; ; ‘ 9355) 
Ferric Oxide, . ; » Ad -BR2 
Ferrous Oxide, . , ft  atieay 
Manganous Oxide, . « elelo 
Lime,. : : : i er 
Magnesia, . : 1 oes 
Water, ‘ i . 7 PALBUS 
100-172 
Loses 10° 454 of the above water at 212°. 
3. GreG and LertsoM, in their “ Manual of Mineralogy,” mention the Giant’s 
Causeway as one of the localities where chloropheite is to be found. I am 
happy to be able, by an analysis of the mineral found there, to show that this, 
which must have been of the nature of a conjecture from similarity of appear- 
ance, was a correct inference. 
That which I analysed was obtained by DurGEoN and myself at the basaltic 
point immediately east of the Causeway; it filled small druses, and also 
coated chalcedony. 
It was much softer than the nail, deep rich brown in colour, unctuous to 
the touch; its streak was shining, and its structure very minutely granular. 
Its specific gravity is 2° 278. 
1‘11 grammes yielded— 
Silica, ; i j ST 
Alumina, . ; ; » 10:°485 
Ferric Oxide, . ; e, Lhe 89 
Ferrous Oxide, . ; . £626 
Manganous Oxide, . : AO TTon 
Lime, . : : ; SP lls; 
Magnesia, . , ODI 
Potash, : ; P : * 338 
Soda, . ; : 3 : ‘761 
Water, : ; : ye2ow203 
99+ 997 
It lost at 212° 14° 156 of the above water. It was readily soluble in acids. 
