98 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
Mr Hannay’s analysis, which I have appended for comparison, shows (as in 
the case of the Catkin mineral) very marked discordance with mine in the mag- 
nesia and alumina. 
Upon pointing this out to Mr Hannay, and asking him to re-examine the 
substance, as I suspected some error had crept into his process, he furnished 
me with the following numbers as the average results of a new inquiry—* 
Silica, é , ' about 38 
Alumina, . s ‘ eet) 
Ferric Oxide, . : es 4 
Ferrous Oxide ney I 
Lime, ; : f As 3 
Magnesia, . i MO 
Water, eS 
Which numbers are more accordant with those obtained by me, with still the 
marked exceptions of the magnesia and alumina. 
The question of this being a new mineral depending upon the quantity of 
these two ingredients, I put a second portion of what Mr Hannay had for- 
warded to me into the hands of Mr Joun Datziet, who has worked in my 
laboratory for several years. 
10. The specimen was hardly so pure as that previously examined, nor was 
it perhaps so absolutely free from calcite, though no effervescence could be 
detected when its powder was placed in acid. 
1°301 grammes yielded— 
Silica, ; 3 474 
From Alumina, . ° 004 
*478 = 36° 741 
Alumina ; oNab"'35 
Ferric Oxide, . ; 22 0! IBS 
Ferrous Oxide, . . 962 
Manganous Oxide, . : "076 
Lime, . : ‘ nf 31056 
Magnesia, : 5 . 20°215 
Potash, . 5 ‘ : * 494 
Soda, : : : , - 206 
Water, . , ‘ e216 
100° 314 
Lost at 212°, 12: 965 of the above water. 
* Undertaken I however understand by two of his students. 
