1888.] Mr W. G. Reid on Carbonate of Lime in Sea Water. 157 
tlie maximum amount of carbonate of lime dissolved, the carbonic 
acid solution had to be left in contact, and agitated with the 
carbonate for five or six days. With the apparatus at our command 
we could not accomplish this, and had to rest contented with the 
results given. 
In the experiments XX. to XXIII. , a crystal of Iceland spar was 
taken. The results show a gradual falling olf in the quantity dis- 
solved. The reason for this I cannot explain, but that it is not due 
to the properties of Iceland spar is shown by the experiments 
XXIV. to XXYII. Tor these another crystal was taken, and after 
each experiment it was washed, dried, and weighed carefully. The 
amount of carbonate dissolved by 117*5 c.c. of sea water (the total 
quantity taken for each experiment) was as under. A is the amount 
obtained by titration (alkalinity), and W the loss as observed by 
weighing. Considering the smallness of the quantity to be 
measured, and the opportunities for observational error, the results 
agree fairly well with each other. 
XXIV. 
XXV. 
XXVI. 
XXVII. 
A 
*0009 grms. 
*0006 „ 
*0004 „ 
*0006 „ 
W 
*0008 grms. 
*0008 „ 
•0010 „ 
*0007 „ 
For the last experiment (XXVII.) the crystal, used in the 
preceding four, was ground to a powder, the grains of whicli 
varied from about 1 mm. square down to impalpability. This 
was done to try the effect of increasing the surface exposed. 
As was expected, the amount dissolved was much greater (six 
times). 
My thanks are due to Mr T. Lindsay for kind assistance in some 
of these experiments. 
