368 Experiments and Obfervations 
there remained a fubftance, extremely tenacious, which had 
much the appearance of gum arabic: its tafte was bitter 
with a flight degree of fweetnefs; when fqueezed between 
the teeth it had exa&tly the feel of gum, but more tenacious 5 
it was not foluble in alcohol, at leaft in any quantity; and 
burned on red hot iron like gum, leavinga bulky and infipid 
‘charcoa]l.—That this converfion of the faccharine principle 
into a gum was effected by the abftraction: of oxygen, is 
highly probable from the nature of the fubftance employed § 
for there are few fubftances which have a ftronger affinity for 
oxygen than phofphuret of lime. 
Solutions of fugar were mixed with different fulphurets, 
and agitated with nitrous gas in clofe veffels. The fulphu- 
rets, efpecially that of potath, deftroyed the faccharine tafte; 
but owing to the folubility of the different produéts, the na- 
ture of the change-could not be accurately afcertained. The 
action of the nitrous gas was more doubtful. 
To be fatisfied how far the effets produced in the former 
experiments might be owing to the abftraGtion of oxygen, 
Mr: C. added to folutions of fugar in water both lime and 
pure potafh, and boiled the mixtures. The lime combined 
with and gave to the fugar a bitter aftringent tafte; but it 
was ftill {weet ; alcohol put to the filtered folution produced 
a precipitate im white flakes, fimilar to that in the experi- 
ment with the phofphuret, and which appeared to be a com- 
bination of fugar with lime. Vitriolic acid likewife precipi- 
tated the lime, in the form of felenite, and in a great mea- 
{ure reflored the natural tafe. Some of the filtered folution 
being evaporated by a gentle heat, there remained a femi- 
tranfparent fubftance, much more tenacious than the thickeft 
fyrup, but lefs fo than that produced by the phofphuret of 
lime: it had a rough bitter tafte, with a certain degree of 
fweetnefs. The potafh likewife appeared to combine with 
the fugar, the fweet tafte being more completely deftroyed 
than by the lime: but on the addition of fulphuric acid ful- 
phat of potafh was formed; and this being precipitated by 
| alcohol, 
