Supplementary Varieties. 
Which’ he’ promises shall be much more ac 
curate and detailed. ©" 
Zinn atl Mice is of'a dilveryswhite ol our, 
ae it ey At odedrs in crystalline 
greys) OF Witt Othe Famine’ are’ flexible, 
elastic, and of considerabte'size.! The spe- 
cifie Sfiavity OF Soiie “boiled In’ ‘distilled 
wate to! etelude the Air, was 2-085. Heat- 
et "£0. rddveeo no’ appreciable weight was 
ios and, Paget) he change of aspect 
d. Te was readily fused by the blow- 
pile fame) whieh Was thet’ tinged with red. 
Tie fiisiow was aeeotnpanied by an appa- 
Feit Boiling) whd’a black’ scorious mass was 
left, “To determine 'thé'alkalies, carbonate 
age aie on 51235 grains of the pow- 
pr... THe ‘mass greatly contracted from 
flie ‘ignition, and assumed a green blackish 
colour. 7°35 #rains ‘of sulphate of lithia, 
faivalent to 2°28! grains, or. 4°09 per 
aed of :pur'e'lithia, resulted from the pro- 
ess “Hbove described’; and 9°68 sulphate 
6f potass; equivalent to 5°28 grains, or 
9467 percent. puré: (Sulphate of potass 
is} here; prestimed''to be composed of 40 
tiric acid and 48 potass ; and sulphate 
of lithia’ of 40 acid and 18 lithia.) The 
determination of the other constituents is 
complicated, ‘owing to the presence of 
fluorie’ acid, Which occurs, perhaps, in all 
micas. ° ' Berzelius’ method, in the analysis’ 
of ‘the t@paz, was resorted to; which, being 
of some ‘delicacy, may be described par- 
fieularly: 29°38 grains’ of the mica, in 
powder, were mixed with thrice the weight 
of carbonate of soda; and ignited in a mo- 
derate red heat, for the space of half-an- 
hour; the mass had then contracted great- 
ly,” and was of a dirty yellowish colour, 
stained green, in parts, by manganese. It 
ome by successive portions of hot 
“till all soluble alkaline matter was 
pic pth removed. Carbonate of am- 
monia was now added.to the alkaline solu- 
tion, éxposed’to 4 ‘temperature aliout 100° 
Fahr’, till the ammoniacal odour had com- 
preeely’ ‘eeased ; ‘by which mean the alu- 
mina‘'and ‘silica’ were ‘deposited. After 
filtration, ‘the Viauid was neutralized by 
miuitiatie’ atid) and the fludric acid dissipat- 
ed sby'mititiate” of Time: The fluate of lime 
having been ignited; weighed 5°41 grains, 
equivalent? £2 “of lime’ containing, in 
100° 738 of fluoric acid) to 1°509 
6F"5"138- per eenit.: ‘of fluoric acid. 
ben rpenmen te d\by’ the water; at 
ef With that afterwards: separated 
Soeekennante soltition,’ was ‘dissolved 
by'mariatie acid! ol"THe'solution was evie- 
nae i et hed soluble parts were 
water, atidulated with muri- 
pero these cdllected on a 
fitess ATP “Spiiition, it! weighed | 15°07 
od8 WO77 per vent: To the acid 
aml ope re so diluted, a 
n-sfledrbonate df be th’ “a 
ade dsl theo aTinisina’ ani itolf Were ‘pre- 
siete osc sepae. 
rated By {iE Potass.° The ahimine’ after ex- 
doidvs 
555 
posure to a white heat, weighed 8349 grains, 
24°532 per cent. The ignited peroxide of 
iron amounted to 3°709 grains, 3 *329 grains, 
or 11°35" per. cent. of, protoxide :. and, ex- 
amination proved this to be pure, «The 
solution, from which the iron and alumina 
had been separated, was boiled briskly, to 
expel carbonic acid, and rendered decidedly 
alkaline by carbonate of soda. A. dirty, 
white precipitate subsided, which, when 
heated to redness, amounted. to. 0543 
grains of the brown oxide, of manganese, 
1-489 grains, or 1°664 per cent. of, the 
protoxide. Examination proved it to con- 
tain neither lime nor magnesia. ». 
The composition is :— a-¥ 
DICH: sasaeanecgos 44-28 | Fluoric acid 5714 
Alumina ......... 24°53 |, Potass)...0.« 9147 
Protoxide of iron 11°33 | Lithia. ......,. 409 
Do. of manganese 1:66 
00°50 
[Dr. Turner, in Brewster's Journal. 
Klaproth’s analysis shows:— 
Silica. ee. QE ‘a7 
Alumina *0lsd 20. 222 2) 2130/0 
Oxide of iron’....c.0. 1550 0990 
Do. of Spero 3 oo OES SOMBIE 
Potass i 5.0. HR 14°50 ini 
98°75 LPO 
Other specimens of mica have liketvise 
been subjected, by Dr. Turner, to the same 
minute analysis, particularly from Alten= 
berg, near Zinnwald ;—a greyish white,’ allt 
a brown mica from Cornwall : m none of 
which varieties was there any presence: “of 
titanium, which (in p. 441, of. vol. Tix! 
M.™M-) is apparently too hastily stated ‘ta 
be a minute constituent of alZ micas; but 
these analyses, which have been subse- 
quently instituted, refer, perhaps, to Va" 
rieties not then known.” It is curious ‘that 
all these micas are found in tin districts ; 
and perhaps future observations on the’ oe. 
currence of Lithton-Mica, may direct the 
practical miner in his search for veins of tin, 
Historical’ Facts.—It is singular that 
parliament has assembled on a Sunday, in 
consequence of the death of the sovereign,, 
no less than three times during the aes 
and the three preceding reigns—in_ that, o 
George I, on occasion of the death of Queen: 
Anne; in George IIT, on occasion of the. 
death of George II. ; in George. EY, on 9¢-; 
casion of that of George Ill, 
equally singular, that the reigns of ne Bales 
three Edwards should have occupied. Dae 
of time considerably exceeding a century : 
and that the reigns of the first «thie Ge 8 
should have occupied a simi ie a 
ward I. ascended to the, thr Ne, 
1272; Edward IT, aN da ds ae iis Baie 
III, Sept. 21, 1327. 
uarehs ruled England, pth se 
and 12 days.” The , fime..9 
réigns of_thr¢e. Georg e551 i} 
midathas" or 20 days P . 
4 B2 ali 
