610 THE POPULAR SCIEXCE MOXTHLY. 



adventure. There are other lizards which have a similar power, though 

 in less degree. The American glass-snake, so called, is one. 



draper describes certain snails of the Philippine Islands which do 

 the same thing : u Every species (ITeUcarion) that I personally exam- 

 ined possessed the singular property ... of shedding their tails 

 when thev are seized somewhat roughly, at a little wav behind the 

 shell. This they do by whisking the tail up and down with extraordi- 

 nary rapidity, almost convulsively, till it drops off ; if the creature is 

 held by the tail it immediately falls to the ground, where it easily hides 

 among the leaves. . . . These snails at first constantly escaped me and 

 my collectors in this way, and not unfrequently we had nothing but 

 the tail left in our hand." 



-+++- 



BRAZILIAN DIAMONDS AND THEIR ORIGIN. 



Br M. H. GORCEIX. 



THE discovery of the diamond-beds of the Cape of Good Hope, 

 with the extraordinary abundance of their yield, seems to have 

 caused it to be forgotten that the empire of Brazil only a few years 

 ago had the monopoly of that precious stone, as it still has of the finest 

 crystals. Hopes have been entertained that the examination of the 

 green serpentine, in which the Cape diamonds are scattered, would per- 

 mit a determination of its origin and its primitive bed. No doubt, 

 however, now exists that the magnificent crystals incased in that rock 

 were already in existence when in its upward course from the depths 

 of the earth it brought them along with it and left them where they 

 are now found. Unless, then, new discoveries are made at the Cape, 

 of beds of a different nature, it will be necessary to look to Brazil for 

 the solution of the question of the primitive bed, the origin and the 

 mode of formation of the diamond a triple problem which appears, 

 down to the present time, to exist as a challenge to all who are occu- 

 pied with geology and mineralogy. 



The diamond has been and still is mined at numerous points in 

 Brazil, which are situated chiefly in the provinces of Bahia, Goyaz, 

 Matto Grdsso, Parana, and Minas Geraes. Except in the last province 

 and in that of Bahia, they give occasion only to the labors of isolated 

 diamond-workers, the garimperos of Brazil, who wash the sands of 

 the streams in large wooden bowls. The principal diggings in Minas 

 Geraes are grouped around the city of Diamantina, which is situated 

 almost on the meridian of Rio Janeiro, about five hundred miles from 

 the coast. A few other districts also furnish small quantities of dia- 

 mond-. VTe shall consider especially the diamond-beds of Diamanti- 

 na ; and we need not then speak of the others, for they are all so 



