712 THE VOYAGE OF THE VEGA. [chap. 



the ridges (osar) and hills with erratic blocks in Sweden and 

 Finland that I was astonished when I saw them. I was com- 

 pelled to resort to the evidence of the palms to convince myself 

 that it was not an illusion which unrolled before me the well- 

 known contours from the downs of my native land. An accurate 

 study of the sandy hills on the Inland Sea of Japan, of the clay 

 cliffs of Hong Kong, and the cabook of Ceylon would certainly 

 yield very unexpected contributions to an explanation of the 

 way in which the sand and rolled-stone osar of Scandinavia 

 have first arisen. It would show that much which the Swedish 

 geologists still consider to be glacial gravel transported by water 

 and ice, is only the product of a process of weathering or, more 

 correctly, falling asunder, which has gone on in Sweden also on 

 an enormous scale. Even a portion of our Quaternary clays 

 have perhaps had a similar origin, and we find here a simple 

 explanation of the important circumstance, which is not suffi- 

 ciently attended to by our geologists, that often all the erratic 

 blocks at a place are of the same kind, and resemble in their 

 nature the underlying or neighbouring rocks. 



It is this weathering process which has originated the gem 

 sand of Ceylon. Precious stones have been found disseminated 

 in limited numbers in the granite converted into cabook. In 

 weathering, the difficultly decomposable precious stones have 

 not been attacked, or attacked only to a limited extent. They 

 have therefore retained their original form and hardness. 

 When in the course of thousands of years streams of water 

 have flowed over the layers of cabook, their soft, already half- 

 weathered constituents have been for the most part changed 

 into a fine mud, and as such washed away, while the hard gems 

 have only been inconsiderably rounded and little diminished in 

 size. The current of water therefore has not been able to wash 

 them far away from the place where they were originally im- 

 bedded in the rock, and we now find them collected in the 

 gravel-bed, resting for the most part on the fundamental rock 

 which the stream has left behind, and which afterwards, when 

 the water has changed its course, has been again covered by 

 new layers of mud, clay, and sand. It is this gravel-bed which 

 the natives call nellan, and from which they chiefly get their 

 treasures of precious stones. 



Of all the kinds of stones which are used as ornaments there 

 are both noble and common varieties, without there being any 

 perceptible difference in their chemical composition. The most 

 skilful chemist would thus have difficulty in finding in their 

 chemical comj^osition the least difference between corundum and 

 sapphire or ruby, between common beryl and emerald, between 

 the precious and the common topaz, between the hyacinth and 

 the common zircon, between precious and common spinel ; and 



