32 A. H. Chester—Artificial Orystals of Gold. 
heat. A series of measurements on a number of these crystals 
P proves them to belong to the hexagonal system, 
having in general the form shown in fig. 3. 
The average of forty-eight measurements of the 
prismatic angle is 119° 58’, the six angles of the 
most perfect one found measuring as follows: 
120° 30’, 121° 6’, 119° 12’, 119° 6’, 120° 36 
1 
and 120° 12’. The angle O a 1 has been 
approximately determined to be about 136°, 
he roughness of the crystals rendering exact 
measurement extremely difficult. The pyra- 
midal planes are sometimes entirely wanting, the 
crystal having only a basal termination. e 
base is often hollow, in one crystal presenting 
the appearance shown in fig. 4, the whole base 
being gone. The sides and bottom of this 
depression are quite rough, and show no attempt 
at regularity. Another termination is shown in 
XQ fig. 5, where part of the base still remains. Fig. 
3 was drawn under a power of 300 diameters, 
: the general shape being retained, but the irregu- 
larities taken away. Itis about 05 mm. in length and 0:06 mm. 
in diameter. The gold used in preparing these crystals should 
“ be pure and in a finely divided condi- 
treated with about twelve parts of mer- 
cury and well triturated in a mortar. 
The amalgam must then be heated to about 130° C., kept at 
5. 
Hamilton College, April 4th, 1878. 
