104 ANNUAL OF SCIENTIFIC DISCOVERY. 



surface on which a number of little triangular forms are observed, may 

 be restored to its original perfect state by dipping the crystal into a so- 

 lution of alum. To use his own words, " The singular fact in this ex- 

 periment is the inconceivable rapidity with which the particles in the 

 solution fly into their proper places upon the disintegrated surface, and 

 become a permanent portion of the solid crystal." 



Von Kobell made the above experiment, without, however, obtaining 

 the same result as Brewster. But the further he went in his investiga- 

 tions, the more wonderful and inexplicable were the revelations that 

 unfolded themselves. The existence of certain infinitesimal combina- 

 tions became evident, which it is as impossible for the human mind even 

 to comprehend, as it is for science to follow or to fathom. In one such 

 crystal is enlocked a world of wonders. Subtle powers are there at 

 work, elementary changes going on, of which, as yet, we have not the 

 slightest, the remotest conception ; immutable laws are there governing, 

 whose existence we have no knowledge of, and whose manifold bear- 

 ings our bounded understanding would be quite .inadequate to grasp. 

 And the more we discover on this particular field, the more are we in- 

 clined to start back in bewilderment at the boundlessness of the horizon 

 which opens before us. 



Well may von Kobell observe, that " theoretic crystallography stands 

 here, as it were, before a mirror, which shows all the difficulties and 

 riddles which must be conquered and solved, riddles which, as yet, it 

 seems, will never be brought to a solution." And he further quotes 

 what Brewster once expressed when writing on the subject : " In 

 whatever way crystallographers shall succeed in accounting for the va- 

 rious secondary forms of crystals, they are then only on the threshold 

 of their subject. The real constitution of crystals would be still un- 

 known ; and though the examination of these bodies has been pretty 

 diligently pursued, we can at this moment form no adequate idea of 

 the complex and beautiful organization of these apparently simple 

 structures." 



One of the discoveries which Professor von Kobell made gives us 

 some insight into the marvels of this organization ; not, however, ex- 

 planatory of it, but showing us, behind newly-discovered wonders, 

 others half-hidden, receding with systematic order into absolute infinity. 



He discovered, namely, that the luminous appearances in calcareous 

 spar are quite different when the surface of the crystal is disintegrated 

 by means of nitric acid from those when muriatic acid is employed. 

 And what is very extraordinary is, that when the corrosion is produced 

 by muriatic acid, a shining figure is called into existence, regularly 

 formed of straight lines ; but when nitric acid is used to corrode the 

 polished face of the crystal, then it is elliptic figures offshoots like 

 tendrils which show themselves. Here then. Ave have, in addition to 

 the final phenomena, the fact that the molecular construction of the 

 crystal is affected by one acid only in one direction, and by another in 

 a direction quite different. How marvellous the combination of the 

 atoms, admitting now a channel between them, and now closing it her- 

 metically against the intruding acid ! What a strange secret of affini- 

 ties and alienation does this disclose of qualities and powers that we 

 cannot even conceive of? On a hexagonal prism of calcareous spar, 

 when the surface is subjected to the corrosive influence of muriatic 



