422 Miscellaneous Intelligence. 



of 4.283 to 4.819. When reduced to powder and boiled in water, 

 a trace of muriate of lime is discoverable. 



It loses nearly the same by exposure to strong red heat as the 

 peroxide, t. e. about 13.26 per cent. ; but on examination, it ap- 

 peared the proportion of oxygen evolved was much less than when 

 peroxide was heated, and the quantity of water more. By close 

 analysis it appeared to consist of, 



Manganese ..... 

 Oxygen ..... 

 Water 



100.0 



Or two atoms deutoxide, three atoms peroxide, and one atom water. 

 Mr. Phillips gives the following view of the known compounds of 



manganese and oxygen : — 



m. o. if. o. 



Protoxide . . .. 1 + 1 28+8 



Deutoxide . . . .2 + 3 28 + 12 



Peroxide . . . 1+2 28 + 16 



Red oxide . . . . 3 + 4 28 + 10.66 



Warwick oxide. . . 4 + 7 28 + 14 



Manganous acid . . .1 + 3 28 + 24 



Manganesic acid . . 1 + 4 28 + 32 



So similar is the new compound to some of the old well-known 

 compound of manganese, that at first some difference of opinion 

 as to its nature took place between Mr. Phillips and Dr. Turner; 

 which has, however, been removed by experiments made by the 

 latter, with a true specimen of varvacite. — Phil. Mag. N.S., v. 209, 

 vi. 281. 



§ III. Natural History. 



1. On the Direction of the Roots and Stems of Plants. — This sub- 

 ject has been examined closely by M. Poiteau, who, in his Memoire, 

 considers several facts, and some theories. He first refers to the 

 well-known experiment by Mr. Knight, in which seeds, made to 

 grow on the circumference of a revolving wheel, threw out their 

 radicles in an inclined direction from the centre of motion, and their 

 plumula in an opposite and equal inclined direction towards the 

 centre of motion. This effect, M. Poiteau says, is simply due to 

 the exertion of a physical law, namely, that when a heavy body is 

 projected into space by any force, as the centrifugal force, in the 

 experiment under consideration, the heavy extremity precedes the 

 lighter. Now, the radical extremity is of greater specific gravity 

 than the leaf end of the plant, and consequently, in the wheel ex- 



