185 
Pacts and observations. 
process, it is said, in conjunction with the method of obtain¬ 
ing cheap oxygen from the manganates of soda, discovered 
by the same chemists, is likely to create a revolution in many 
industries, and especially in metallurgy.— Journ. Chem. Soc. 
On a New Reagent for Alkalies. —The fresh leaves 
of Coleus Verschoffelti, an ornamental plant, are put in a glass 
bottle and covered with absolute alcohol, containing some 
drops of sulphuric acid, and macerated twenty-four hours, 
when the fluid is decanted and other leaves introduced 
into the same vessel after the exhausted leaves are removed, 
the liquid being retained. The tincture thus obtained is 
charged with the colouring matter of the leaves ; it is filtered 
and strips of paper are introduced, which are then dried in 
the air. 
The best paper thus obtained has a magnificent red colour, 
which passes more or less to a fine shade of green, by the 
action of alkalies and alkaline earths. The author considers 
it better than reddened litmus because more sensitive; it is 
not modified by carbonic acid, but should be kept close.— 
M. Boettger, Journ . cle Charm. 
On the Influence of Sugar on Magnesia used as 
an Antidote. —In 1846 M. Bussy, and afterwards Christison 
and others, recommended magnesia as an antidote for arsenic 
and other metallic poisons. M. Carles, supposing that sugar 
(as in the case of lime) would, by rendering magnesia solu¬ 
ble, increase its efficacy, tried the mixture of sugar, water, 
and magnesia; but, to his surprise, found that it rendered 
the arsenite of magnesia soluble, and that sugar tends to pre¬ 
vent the formation of arsenite of magnesia, and is therefore 
useless and pernicious. 
When, however, saccharated magnesia is used with the 
salts of lead, copper, antimony, and mercury, it hastens and 
facilitates their decomposition without uniting with them, 
and in some instances the sugar of itself acts by reducing the 
oxides. For this last reason it may be better to use honey 
in lieu of sugar. 
In conclusion, except in the case of arsenic , the association 
of sugar with magnesia augments the efficacy of the base 
employed as a general antidote. Two and a half drachms of 
magnesia, five or six drachms of sugar, and three fluid ounces 
of water (boiling), appear to be the most convenient propor¬ 
tion.— Repertoire de Charm. 
