442 NATURAL HISTORY MISCELLANY. 
the cilium attached and the indigo still in the cells. x 
This, I think, will break down Hackel’s hypothesis, which is 
imaginative and incorrect as it is beautiful. 
His “ Magospheera,” too, is figured in the “ Annals” (1856), and 
described in extenso as the ameeboid cell which inhabits the mucus 
of the cells or internodes of. the esar great Nitella. rb 
novelties now.—H. J. Carrer, in Annals and Mag. N. History. 
‘GEOLOGY. 
Rocks Po.isuep py Sano. — Dr. Kneeland, at a meeting of the 
Boston Society of Natural History, exhibited several specimens: 
of glass, marble and hard stones engraved, carved and grooved | 
by the action of sand driven by a blast of air or steam. The 
supposed, by the elasticity of the paper or metal. He drew at- 
tention to this industrial process as illustrating the advantage i: ; 
pare ' the industrial arts, is simply carrying out what natural 
forces have heen doing to the surface rocks of our continent for 
been protected by garnets, projections were left, tipped ge 
bar garnets, pointing like ngere inthe direction of th 
