1818.] some remarkable Minerals. 195 



bring away some of the sand for further examination. It was 

 therefore highly satisfactoiy to me to receive a short time ago, 

 from the Rev. Dr. Satterthivaite, of Lmother Rectory, near 

 Penrith, a parcel of sand, taken from the shore of the remote 

 island of Jean Mayen, in the Greenland Seas, which immediately 

 reminded me of the sand of Canna. It was supposed to be 

 ferruginous ; owing to the partial action of the magnet upon some 

 of its particles. Dr. Sattert/ncaite, in his account of it, relates 

 that " a few weeks before he sent it, he had been on board a 

 vessel, just returned from the Greenland Seas, and had conversed 

 with a very intelligent ship-captain ; who, during his last voyage, 

 had landed on the island of Jean Mayen, in 71°. N. L; an 

 island seldom visited by the English fishermen ; where he found 

 the shores, to an immense extent, and of unknown depth, 

 covered with this kind of sand." It has ajef-black colour, and 

 a glittering appearance ; owing to innumerable particles of 

 minute crystals, of the highest transparency, with a splendent 

 adamantine lustre. As these crystals differ in lustre from 

 olivine, and agree with olivine only in their colour and infusi- 

 bility before the common blow-pipe, I suspected that they might 

 possibly belong to one of those varieties of zircon, which have 

 sometimes been confounded with olivine, when mixed with 

 basalt in the arenaceous form. This suspicion was further 

 increased by examining them with a lens and perceiving that in 

 some instances a right prism with a square base might be dis- 

 cerned ; or with a base so slightly rhomboidal, as not to be 

 thus distinguished from a square. Having therefore selected a 

 rrystal of this form, but so exceedingly minute as scarcely to 

 be discernible to the naked eye, I fixed it upon the moveable 

 plane of Dr. Wvllaston's reflecting goniometer. A double 

 image was reflected by one of the planes of the crystal, but the 

 image reflected by the contiguous plane was clear and perfectly 

 perceptible, by which I was enabled to measure the angle of 

 inclination; and after repeating the observation several times 1 

 round it, to equal 92° or 92-1°. Hence it is evident that these 

 rrysla/s are not zircons, although they possess a degree of lustre 

 quite equal to that of zircon. In this uncertainty 1 sent a small 

 portion of the sand to Dr. Wollaston, and requested that he 

 would hraoseW measure the angle of the particles exhibiting 

 splendent surfaces. Dr. W. pronounced the substance to be 

 pyrownc ; having an angle, according to his observation, of 

 ' »-' V°. He also informed me that the sand was similar to that of 

 BoUerma in Italy. 



Dr. Satterfhuaile now sent me three specimens of different 

 -instances which had all received the appellation of lava, from 

 the same island of Jean Mai/en; and in every one of these 1 

 had the satisfaction of seeing the same crystals'in their matrices ; 

 exhibiting the same splendent lustre, but under more visible 

 ••irciin^hniri a of form and cleObaj&i In the first specimen they 



