336 M E M O I R S of the 
Native vitriol, rubbed with fteel, fhewed that it came nearer 
the nature of iron than copper, having nothing of the rednefs of 
copper in it 5 which the native vitriol, like Amianthus, diffolved 
and fliot into cryftals does alio confirm j for it has at firft a 
fwectifh iron-tafte like that of the fait or folution of iron ^ the 
cryltals do not (hoot like thofe of Go/ler j having firft depurated 
the Iblution by pouring urine into it, and removing the Faeces, 
there came a foliaceous fort of earth, and the remaining liquor 
prefented to the view cryftals almoft of the colour of laphire, 
and of unequal angles j after the folution grew thicker, was filter- 
ed and evaporated, it yielded a white oil, which being put into a 
retort, and gently calcined in an oven, it produced in 24 hours 
very good fpirits of vitriol, fuch as are prepared in the /hops of 
the oil of AUrs 5 by a microfcope, M. Hartman difcovered a 
good deal of fait ftill remaining m the Caput Mortuum of the 
oil, whence may be underftood in what manner the oil contained 
in the Caput Mortuum^ when expoled to the air, may be reduced 
again: Several trials made by fire confirm, that the barky earth 
is of the lame nature with the foffile wood j it muft be roafted 
gently before any metal can be extra61ed out of it, the' what is 
fouml therein is but very little 5 he alio diftilled from the blue 
clay a volatile Ipirit of a fulphureous and bituminous fmell, and 
which floated a-top^ he found that the yellow earth inclined 
fomewhat to the nature of iron, and both its tafte and fmell 
fhewed that it had borrowed fome tindure from vitriol. 
T^he Generation of Fleas; hv S. Diacin£lo Ceftone. Phil. 
Tranf. N® 249. p. 42. 
FLEAS bring forth eggs, or a fort of nitts, from which are 
hatched worms, that make bags for themfelves, like thofe of 
filk-worms, out of which bags come fleas; they depofire their 
eggs on dogs, cats, men, and other animals that are infefted with 
them, or in places where they fleep, which being round and 
fmooth flip commonly down to the ground, or fix themfelves in 
the folds and other inequalities of the coverlets and cloaths ; from 
thefc are brought forth white worms of a fhining pearl-colour, that 
feed on the bran-like fubftance which fticks in the combs, with 
which puppies are combed to takeout the fleas, or on a certain 
downy fubftance found in the folds of linen-drawers, or in other 
fuch like things; in a fortnight's time they come to the 
bignefs of Fig. i. Plate X. and are very lively and aflive; if 
they are under any fear, or if they are touched, they roll them- 
lelves up of a fudden, and make as it were a ball 3 a little after 
they 
