A6 REPORT—1868. 
The author's definition of a chemically clean surface is as follows :— 
A chemically clean surface is one that has on it no film or coating of any sub- 
stance whatsoever foreign to its own composition. As oxidation by the air, organic 
matter, and floating motes are the most usual forms of films, it may be said loosely, 
that any substance that has been exposed for some time to the air is chemically 
unclean; but speaking strictly, a film of any foreign matter will render a surface 
unclean for some conditions or other in the experiments in hand, 
A chemically unclean surface, then, may be generally detined as anything that 
is exposed to the products of respiration or of combustion, or to the touch, or to 
the motes and dust of the air, and so becomes covered with an invisible film more 
or less organic. So also any vessel or surface wiped with a cloth that has been 
exposed to the air is chemically unclean. 
Note on Sea-water. By Professor J. A. WanxKLyn. 
It has been shown during the past year that deep spring-water contains no organie 
nitrogenous matter, and that the water of rivers and lakes contains nitrogenous 
organic matter in the proportion of about one part of nitrogenous organic matter to 
a million of water. The water of the sea contains about one hundred times as much 
solid matter as the water of rivers and lakes. The author asked himself the ques- 
tion whether the nitrogenous organic matter increases in anything like that pro- 
ortion. An examination of sea-water collected off the coast of Devonshire (at 
het encae has been made accordingly, with the object of answering this query. 
The result is that there is about double or treble as much nitrogenous organic 
matter in sea-water; so that the total solids increase far more rapidly than the 
organic matter. 
Researches on the Ethers. By Professor J. A. Wanktyy, 
Five eubic centimetres of good acetate of ethyl and 0:3 erm. of sodium were 
sealed up in a small glass tube, and then heated in the water-bath to 100° C. until 
all the sodium had disappeared. The tube was then opened under water, and the 
gas which escaped measured 25 cubic centims. at the ordinary temperature of the 
air, Reduced to 6° C. and 760 millims. pressure (dry), the volume of the escaped 
gas is about 23 cubic centims. If the volume of hydrogen which is equivalent to 
0:3 erm. of sodium be calculated, it will be found to be about 140 cubic centims. 
Therefore this experiment establishes the fact that there is no evolution of hydro- 
gen as a main product of the action of sodium on acetic ether. Moreover the 23 
cubic centims. of gas which escaped must be regarded as due to traces of alcohol 
in the acetic ether, and not as arising from minor secondary reactions on the acetic 
ether. About 2 per cent. of aleohol present in the acetic ether (and such a quan- 
tity was very probably there) is sufficient to account for 23 cubic centims. of hy- 
drogen, Another sample of acetate of ethyl, which had been very carefully pre- 
pared, evolved no gas at all when acted on by potassium or sodium. 
Acetate of Amyl and Sodium.—The acetate of amyl was very carefully deprived 
of all traces of amylic alcohol by being treated with glacial acetic acid and hydro- 
chloric-acid gas. After this treatment it gave correct numbers on titration. 0:6 
erm. of sodium and 11 cubic centims. of acetate of amyl were sealed up in a small 
tube and heated to 100° C., until all the sodium had dissolved ; the tube was then 
opened under water. Not a trace of gas was evolved. (Calculating the quantity 
of hydrogen equivalent to the 0:6 grm. of sodium, it will be found to exceed 250 
cubic centims. ) 
Butyrate of Ethyl and Sodium.—tThe ether hoiled at 118°-5 C., and was conse- 
quently the normal (not the iso-) butyrate. On being titrated it gave very correct 
numbers. 37 grms. of this butyric ether, 7:5 grms. of sodium, and 40 cubic cen- 
tims. of dry common ether, 
C,H; | 
0, H, 5% 
were sealed up and heated very gently in the water-bath, and shaken up well 
