142 Scientific Proceedings, Royal Dublin Society. 
Secrion I1].—Tur Avurnors’ EXPERIMENTS ON THE ACTION OF 
Baryta WATER ON GLAss AND ON SILICA, AND THE DISTURBING 
EFFECT OF SOLUBLE SILICATES ON THE DELICACY OF THE PHENOL- - 
PHTHALEIN COLOUR REACTION. 
Action of Dilute Baryta Water on Glass.—At the outset of the 
investigation just described, two sets of experiments were made 
which satisfied us that a weak baryta solution has an appreciable 
action on glass, and that this action has a disturbing effect on the 
titer of the solution. They were as follows :— 
(1). A measured volume of the baryta solution was placed in a 
weighed platinum dish, and evaporated with excess of the standard 
hydrochloric acid solution, and the residue heated until of constant 
weight. 
Residue obtained, E . 0°518 grm. 
(2). The same volume of the baryta solution was placed in a 
stoppered Winchester quart, the latter was then well shaken 
and placed on its side for 48 hours. The solution was next poured 
into a weighed platinum dish, the bottle washed out with distilled 
water, and the washings added. ‘The whole was then treated as in 
the first experiment. 
Residue obtained, : . 0°534 grm. 
(3). The experiment was performed as in the preceding case, 
but the baryta solution remained for 72 hours in the bottle. 
Residue obtained, : . 0°560 grm. 
(4). 50 ec. of the baryta solution (1 cc. =1c.c. of standard 
acid) were allowed to remain in a Winchester quart, full of air, 
from which the carbonic anhydride had been removed (as described 
on p. 128) for 65 hours, and then titrated in the vacuum apparatus. 
Standard acid required, . . 48°9 c.c. 
(5). Duplicate experiment to (4), but in another bottle. 
Standard acid required, . > pil GG: 
We now proceed to describe in detail the additional experi- 
ments we made to decide definitely as to the extent and nature of 
