154 On the Presence of Chlorine 



XIV.. — Ground-plan of a building, very simple. 



XV. — A man in a helmet, seated ; upon the seat there is repre- ' 

 sented a hand cut off. Another man in a helmet, a girdle in his 

 left hand, marked with arrow-heads, and holding an instrument 

 in his other hand, in an attitude as if to cut off the left hand of 

 the man upon the seat. These have the long-shaped head. 



XVI.— A circle, in which is a couch, or seat, formed of a qua* 

 druped, like a cat, with a head at each end, and at one end a 

 human face, or head ; a man sits, upon the seat with his legs 

 under him, and his right hand upon his breast ; a human hand 

 and some flowers are upon his head. A figure, apparently a 

 female, kneeling, presents to bim a flower-pot, with a plant in it ; 

 both of these have long-heads. - There is some border- writing, 

 among which are four human heads. Underneath, upon a stone, 

 there is more border-writing, two small human figures, and one 

 head. 



XVII. — An ornamental front, or entrance to a building, deco- 

 rated with two birds and two snakes. The design, on the whole, 

 is not devoid of taste. 



[To be continued.] 



On the Presence of Chlorine in the Black Oxide of Manganese^ 



[By James F. W. Johnston, A.M.] 



i. I digested the native black oxide with the sulphuric acid 

 of commerce : an odour of chlorine was in a short time per- 

 ceptible, and was discernible for many weeks on stirring with a 

 glass rod. 



ii. The brown oxide, remaining after preparing oxygen from 

 the native oxide by exposing it to a red heat, was treated in 

 the same way, and with the same result, 



iii. Another portion of the same brown oxide was washed 

 with repeated affusions of hot and afterwards with cold distilled 

 water. On drying and pouring upon it concentrated sulphuric 

 acid, the result differed in nothing from the former. 



iv. An impure sulphate of manganese was precipitated by 

 carbonate of soda; the carbonate, washed, dried, and heated 

 to redness, gave a brown oxide, which, with sulphuric acid, 

 afTorded precisely the same evidence of the presence of chlorine. 

 The odour was distinct, and the supernatant acid destroyed the 

 colour of indigo. I found & few minutes sufficient to develop 



