> 
Soe Miscellanies. 
be be “3 ay * 
of the moon-culminating stars, which are observed at the same time 
the meridian circle. For latitude, the transit is placed east and 
we 
The Altea: Gaerteiory. may serve as a model of sucha small 
observatory, and the yearly journeys of the Russian astronomers 
from Dorpat, as models for the use of the instruments in determining 
geographical positions. The observations of Professor Schwerdt, of 
Spire, will be found useful in the application of the meridian circle. 
Such a small observatory will be well adapted to form observers; 
as the art of handling instruments so as to obtain accurate results is _ 
only to be acquired by practice. 
Dr. Patterson made the following verbal communication :— 
That the use of the wax tablet written on with an iron stylus, as 
practiced by the ancient Romans, had been tried, for the first time, 
this day, at the Pennsylvania Institution for the Instruction of the 
Blind, and that the success had been perfectly satisfactory. The 
blind read, with ease, the words written, traced geometrical figures, 
&c. It is confidently believed that the Roman tablet will prove of 
great importance in the instruction of the blind. 
Professor H. D. Rogers made a verbal communication, in which 
he called the attention of the Society to a new compound of plati- 
num, discovered by himself and his friend, Martin H. Boyé; upon 
the further investigation of which they are at present occupied. 
It is a well characterized salt, composed of the deutochloride of 
platinum, and the binoxide of nitrogen, in which the former may be 
conceived, in accordance with the views of Professor Hare, to act the 
part of an acid, while the binoxide of nitrogen is in the relation of a 
base. at is of a bright gamboge yellow, is distinctly crystalline, 
though, in consequence of the minuteness of the erystals, their form 
has not been determined. It is highly deliquescent, absorbing water 
at ordinary temperatures, with great avidity, from the atmosphere- 
It is rapidly decomposed by the mere addition of water, which 
causes an active effervescence ; the binoxide of nitrogen being copl: 
ously evolved, and the deutochloride of platinum remaining ae. 
lution. 
This interesting compound is best procured by evaporating @ sl 
tion of platinum in agua regia nearly to dryness, and then adding @ 
large excess of fresh nitro-muriatic acid by small quantities at a time. 
oere compound may thus be readily procured by filtering and pres 
d th 
ing the powder between folds of bibulous paper. Shoul e con- 
centration of the liquid be carried too far, it is requisite to add a little 
water, just sufficient in quantity to preserve the mass in a semi- ui 
ition, and to prevent the precipitation of any deutochloride of 
platinum. 
