476 REPORT—1868. 
6. In order to determine the amount of sodium used in the reaction, it is 
necessary to know accurately the percentage of the sodium in the amalgam. 
Two determinations of this percentage were therefore made. 
I. 10°4695 grms. of the amalgam were left in contact with standard sul- 
phuric acid, and, when gas ceased to be evolved, excess of acid was 
titrated with standard caustic soda. 
It was thus found that 
10-4695 germs. contained -1794 grm. sodium. The amalgam therefore con- 
tained 1-714 per cent. sodium. 
II. 8-015 grm. amalgam were boiled in a flask with water till there was 
no perceptible evolution of gas. The caustic soda produced was 
titrated with standard sulphuric acid. 
It was thus found that 
8-015 grms. contained ‘1403 grm. sodium. The amalgam therefore con- 
tained 1-750 per cent. sodium. The mean of these determinations 
gives 1-732 as the percentage of sodium in the amalgam. 
7. One hundred cub. centims. absolute alcohol were added to each of 
eight carefully dried Woulfe’s bottles. Carbonic acid was passed for an hour, 
in order thoroughly to saturate the alcohol, and then sodium-amalgam added 
to each bottle by means of a glass-stoppered neck. For reasons which will 
be subsequently understood, the last four bottles were detached after about 
twelve hours, and the reaction went on in them without any more carbonic 
acid being passed. 
The gas was passed through the other four bottles for three days, the 
temperature of the alcohol, for nearly the whole time, being several degrees 
below 0° C. 
8. Before describing the method of examining the product of the reaction, 
a few words of explanation are necessary. If sodium is dissolved in abso- 
lute alcohol, sodium-alcohol is formed and hydrogen given off. If dry car- 
bonic acid be passed into the sodium-alcohol, the sole product is ethylearbonate 
Na \o. this 
compound is decomposed by acids into alcohol and the sodium-salt of the 
acid ; by oxalic acid, for instance, into alcohol and oxalate of sodium. 
Now if a known weight of sodium be added to absolute alcohol, and 
whilst the sodium is dissolving a current of dry carbonic acid be passed, it 
is found that the number of cub. centims. of standard acid required to neutralize 
the ethylcarbonate is less than is equivalent to the sodium used. If W be the 
weight of sodium used, and w the number of cub. centims. of standard oxalic 
acid, containing 63 grms. crystallized oxalic acid in the litre, required to 
neutralize the ethylearbonate, x x -023 is less than W, and W—«# x -023 is 
the amount of sodium incapable of neutralizing standard acid, and which, in 
fact, exists as sodium in salts of acids formed synthetically. 
9. If sodium amalgam and carbonic acid act upon alcohol, in order to 
determine the sodium used in the reaction, we must know,— 
i. The amount of sodium in the sodium-amalgam. This is determined by 
calculation from the weight of amalgam used and the percentage of sodium 
it contains. 
i. The amount of sodium left in the amalgam after stopping the reac- 
tion. This is determined by leaving the residue of amalgam in contact with 
fo sulphuric acid, and determining excess of acid by standard caustic 
soda. 
i, minus ii. gives (w) the sodium used in the reaction; and if, as before, x 
of sodium, to which has been assigned the formula CO, 
