1888. | Mr D. J. Carnegie, On the Iodides of Copper. 307 
will in general determine the orientation of the axes of the 
ellipsoids. It is then shewn how the arrangements of the ellip- 
soids are related to the crystalline forms. If the three axes of 
the ellipsoids be all unequal the crystal will be anorthic, oblique, 
or right prismatic, according to the orientation of the axes. If 
two of the axes be equal so that the ellipsoids become spheroids, 
the crystal will be rhombohedral or pyramidal, according to the 
orientation of the axis of revolution of the spheroid, or in the 
case of special relations between the axes, cubic with cubic 
cleavage, or cubic with dodecahedral cleavage. If the three axes 
be all equal the crystal will be always cubic, but with a predomi- 
nant octahedral cleavage. 
(2) On the metameric transformation of Ammonium Cyanate. 
By H. J. H. Fenton, M.A., Christ’s College. 
WITH a view of investigating the class of changes known as 
isomeric and metameric, the author has prepared ammonium 
cyanate In a pure state, and has studied the conditions of its 
transformation into urea. The results indicate that the change 
proceeds rapidly at first, then becomes slower, and ultimately 
reaches a limit which is a function of the temperature. In no 
case examined was the transformation completed: even at 100° C. 
for 20 hours only 88 per cent. was transformed. 
Conversely, experiments render it highly probable that urea 
in solution is, in part, re-transformed into ammonium cyanate, 
so that the phenomena may to some extent be compared with the 
allotropic changes of phosphorus, &c. 
(3) On the Iodides of Copper. By D. J. Carneciz, B.A, 
Gonville and Caius College. 
SOLUTIONS of Cul, containing about ‘3 gram in 100 cc. have 
been obtained. The author’s experiments render it very probable 
that when potassium iodide is added to an aqueous solution of 
copper sulphate, in molecular proportions, cupric iodide is produced 
but the whole of the potassium iodide is not decomposed, and that 
the remaining KI reacts with the Cul, produced to form Cul and 
HL. ol: 
(4) On a Compound of Boron Oxide with Sulphuric Anhydride. 
By R. F. D'Arcy, B.A., Gonville and Caius College. 
By the reaction of boric acid with sulphuric anhydride, or with 
concentrated sulphuric acid containing a large quantity of sul- 
phuric anhydride, a definite compound having the composition 
BH,(SO,), has been obtained. 
