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TRANSACTIONS OF THE SECTIONS. 37 
farmer may learn with certainty, that if his fields produce five quarters of wheat per 
acre, that grain carries along with it to the market forty pounds weight of the earthy 
material of each acre of ground. It must be obvious that if this be not restored in 
“quantity and quality, in the shape of manure, his fields must be correspondingly 
impoverished. 
Several substances, particularly nitric acid, were tried in order to ascertain if any 
chemical preparation could be added to the specimens experimented upon, before or 
during the combustion, which would facilitate the otherwise tedious process ; but they 
all failed to give satisfactory results. The per-centage left by nitric acid was always 
less, but not uniformly less than it ought to have been. 
- 
Analysis of three species of Fucus. By E. G, Scuwe1rzer. 
The author described his method of analysis, and remarks, if we refer to the table 
of analyses there will be perceived a marked difference in the proportions of the va- 
rious ingredients, particularly between those of the Laminaria and those of the two 
other Fuci, which difference may offer no small advantage to agriculture. We have in 
the Laminaria saccharina the alkaline carbonates predominating, whereas in the two 
other Fuci, the sulphates. The preponderating quantity of potassa over that of soda 
in the Laminaria is remarkable ; it contains 22-4 per cent. of potassa to 18°8 per cent. of 
soda, whilst Fucus vesiculosus has 17:4 per cent. of potassa to 27-4 per cent. of soda, and 
Fucus serratus 15 per cent. of potassa to 25 per cent. of soda. But sea-water contains only 
in 1000 parts 0°76 chloride of potassium to 27:05 of chloride of sodium ; it is there- 
fore obvious that by the influence of vitality the potassa must have been powerfully 
attracted and assimilated ; asimilar fact is more particularly evinced in the quantity of 
iodine, of which the Laminaria contains 3:6 per cent., and the sea-water scarcely one- 
millionth part of its own weight. However, all the ingredients contained in sea-plants 
must have been derived from the sea-water, and though phosphoric acid is not dis- 
cernible in the residue from the evaporation of the quantity of water usually employed 
in quantitative analysis, nevertheless there can be no donbt that it exists in it, and 
“would be found if larger quantities of water were subjected to analysis. 
An experiment was performed to ascertain if iodine is exhaled from the Laminaria 
saccharina when exposed to the rays of the sun. Several pounds of this sea-weed 
were introduced into a large glass vessel, closed by a cork, from which was suspended 
a small vessel containing a weak solution of nitrate of silver and a slip of paper with 
amylum paste. This apparatus was for six weeks subjected to the direct influence of 
a summer’s sun (but so that the rays did not fall upon the tests), yet no turbidity in 
the silver solution, nor any reaction upon the amylum paste was visible. But I have 
to notice the fact that the plant began slightly to ferment, and that the glass vessel was 
filled with alcoholic vapours. - It has been asserted that the saccharine matter in this 
Fucus is only mannite, but we know that mannite does not undergo fermentation, it 
must therefore contain another substance, from which the vinous fermentation pro- 
ceeds. This will form a subject for future inquiry. The slimy fluid of the Laminaria 
in its fresh state is perfectly neutral, but when exposed to the air it soon indicates an 
acid reaction. Eight ounces of this Fucus were mixed with pure water and distilled, 
but neither in the distilled fluid was iodine indicated, nor was a slip of paper with 
amylum paste, kept during distillation before the tube that conducted the vapours, 
' acted upon. The distilled fluid contained no essential oil, but was strongly impreg- 
: 
nated with the peculiar odour belonging to sea-plauts, which odour seems therefore 
not to be derived from the presence of iodine, or if so, the olfactory nerves must be a 
superior test to those employed. I have omitted to state that the above Fuci indi- 
cated but faint traces of bromine in 50 grs. of ashes, 
