10 ROYAL SOCIETY OF CANADA 
for example, methyl’ and ethyl orthosilicates, formed by acting upon 
silicon tetrachloride with methyl and ethyl alcohol respectively. Ethy] 
metasilicate is also said to have been prepared. As simple examples of 
a natural orthosilicate and metasilicate, we may take chrysolite and 
wollastonite : 
SL De Si > Ca. 
£ o> Mg 
CHRYSOLITE. WOLLASTONITE, 
By the elimination of one molecule of water from two molecules of 
metasilicie acid we should expect to get meta-disilicic acid H,Si,0,, thus : 
O | 
ZT OH SE 
0H Hire 
= 0 — O 
OH | 
Si. —OH Si ee 
ee < 
TWO MOLECULES META-DISILICIC 
METASILICIC ACID. ACID. 
A compound agreeing fairly well with this formula has been obtained 
by Merz (Jour. f. Pract. Chem., 99, 1771). As an example of one of 
its salts, we may take the minerals petalite LiAl(Si,0,;), and titanite 
CaSiTiO,. 
By the abstraction of a molecule of water from two molecules of 
orthosilicic acid, the resulting acid would be ortho-disilicic H,Si,O,, thus : 
0H à 
on emg 
sa Sit UF 
OH On 
OH à 
> — H,0 = O 
OH 
i /_- OH 
Sn sion 
OH OH 
TWO MOLECULES ORTHO-DISILICIC 
ORTHOSILICIC ACID. ACID. 
Though this acid has not been isolated, both its methyl and ethyl 



1 The vapour density of methyl orthosilicate is 5°88 (cale. 5°26). 
2 Merz found that the gelatinous compound formed by decomposing SiF, with 
water, after drying for six weeks in air at 20°-25° C., contained from 13°] to 13°5 per 
cent of water. The formula Si,0;H» requires 13°05 per cent. Groth, however, states 
in his ‘‘ Tabellarische Ubersicht der Mineralien,” p. 93, that the acid Si,O;HL is not 
known in the free condition. 
