1888.] Mr W. G. Reid on Carlonate of Lime in Sea Water. 153 
water, noting the temperature, and the pieces of india-rubber tubing 
at each end securely clamped. The tube C is attached and secured 
with wire, then filled with mercury, and another bulb, also accurately 
measured, and filled with carbon dioxide at a known temperature and 
pressure, is attached in the same way as B, to the other end of the tube. 
The clamps are now unscrewed, and the carbon dioxide is allowed to 
come in contact with the water, and as it is absorbed the vacancy so 
caused is filled up by allowing mercury to be sucked in. When the 
carbon dioxide is all dissolved, the mercury is allowed to flow to 
the smaller bulb (always that which contained the carbon dioxide), 
which may be detached after clamping the rubber tube at the 
bottom of tube C. Where pressure is applied, the mercury is 
forced up into the bulb, and the water into the funnel, the air in 
which at the pressure employed (4 tons per square inch, or nearly 
600 atmospheres) contracts to a very small bubble, and thus allows 
the water to come into contact with the shells. In these experi- 
ments the pressure was kept at its maximum for 30 minutes, then 
released, and again applied and kept up for 60 minutes. When 
the pressure is let off, the air expands and drives the water out of 
the funnel ; the effect therefore of the break in the application of 
the pressure is to cause a slight agitation, and to bring a fresh 
portion of the liquid into contact with the shells. After each experi- 
ment the alkalinity of the water was carefully determined, and the 
original alkalinity deducted therefrom: the quantity of carbonate 
of lime dissolved was thus ascertained. 
Each of the experiments made under pressure w^as repeated, 
at the ordinary pressure, under as nearly as possible the same 
conditions. The funnel taken in this case was larger, and a 
scratch on it indicated the capacity of the funnel used for the corre- 
sponding pressure experiment. A glass cover protected the con- 
tents of the funnel from dust. The lower end of the bulb B 
was attached to a tube which passed through an india-rubber 
stopper in one neck of a small Woolff’s bottle, through the other 
neck a funnel tube about 20 inches long was passed. Both 
tubes dipped under the surface of mercury contained by the 
Woolff’s bottle, and by pouring mercury into the funnel tube, 
the water was forced into the funnel until it reached the scratch 
aforementioned. 
