<255 
manure as soon as the vegetable fibre is removed 
from it. 
Sea weeds, consisting of different species of fuci, 
algae, and confervae, are much used as a manure 
on the sea coasts of Britain and Ireland. By di- 
gesting the common fucus, which is the sea weed 
usually most abundant on the coast, in boiling 
water, I obtained from it one- eighth of a gelatinous 
substance which had characters similar to mucilage. 
A quantity distilled gave nearly four-fifths of its 
weight of water, but no ammonia ; the water had 
an empyreumatic and slightly sour taste ; the ashes 
contained sea salt, carbonate of soda, and carbo- 
naceous matter. The gaseous matter afforded was 
small in quantity, principally carbonic acid and gase- 
ous oxide of carbon, with a little hydro-carbonate. 
This manure is transient in its effects, and does 
not last for more than a single crop, which is easily 
accounted for from the large quantity of water, or 
the elements of water, it contains. It decays with- 
out producing heat when exposed to the atmo- 
sphere, and seems as it were to melt down and 
dissolve away. I have seen a large heap entirely 
destroyed in less than two years, nothing remaining 
but a little black fibrous matter. 
I suffered some of the firmest part of a fucus to 
remain in a close jar containing atmospheric air for 
a fortnight : in this time it had become very much 
shrivelled ; the sides of the jar were lined with 
dew. The air examined was found to have lost 
oxygene, and contained carbonic acid gas. 
Sea weed is sometimes suffered to ferment before 
it is used; but this process seems wholly unne- 
