[ 4§7 ] 
peared, at a little diftance, to be roundifh, but on 
examining, narrowly, their Tides were found to be 
made up of five or fix flat furfaces ; and ge- 
nerally one end of each cryftal was made up of 
two flattifh fides, which role like a wedge which did 
not come quite to a point, but left a ftnall narrow 
furface between. 
Thefe chryftals, in the mouth, imprefs at fir ft a 
very flight faltifh, and fo me what fweetifh cool tafle ; 
which is by no means unpleafant, and refembles a 
good deal that of the fait of lemons. They did 
not affed the thermometer in the time of their folu- 
tion in water. 
Experiments III. and IV. 
With the acid of Sevill oranges, and of peaches. 
It being late in the fummer before I made any ex- 
periment with the juice of the Sevill oranges, I could 
get none of this fruit but what had been long kept 
and was fhrivelled, in fo much that a dozen and 
a half of the oranges did not yield more than half 
a pint of juice, which had loft a great deal of its 
acidity, and faturated but a very fmall quantity of the 
alkali ; and on cryftalliflng I could obtain no other 
fait but a few very frnall cubical or fquare cryftals, 
luch as are reprefented by fig. 3. and fimilar to the 
fait got in an experiment I made with peaches, as 
may be feen in fig. 4. A faponaceous or mucous 
matter, with which thefe faturated juices abounded, 
feemed to prevent the cryftallifation of the falts. 
4 
As 
