Bibliography. 383 
tesa and seein sand,* 8-780 grs. Oxygen. 
Silicic ig , - 23°620 12-275 
note cid, : . ‘ 8-000 5°788 18°135. 
Sulphuric aaa ur ; . 0-137 0-072 
Lime, . “ : - 47-285 13-281 
‘Alumina, ‘ ‘ é . 6120 2941 
Peroxide of iron, . , i 3°260 0-998 18-190 
agnesia, , ‘ ' - 1/920 0-760 
Manganese (oxide of), . » <7 100 0-077 
(| ae pets . 0-792 0-133 
100-014 
‘014 gain, ashes. 
100-000 
Oxygen of the acids=18-135 
Oxygen of the bases=18-190 
‘One hundred grains of the Rosendale cement yielded, on analysis, as 
follows :— 
Silicie acid, . ‘ . . 18°170 grs. con. 4 439 
Sulphuric acid, . ‘ : 1-000 0-5 sf 12-93, 
Carbonic acid, ‘ . + 2°893 
Lime, F ;. 44-970 
Magnesia, 19-0S0 7360 7 
Alumina, . pe 5°500 2°563 
Peroxide of i iro, ; ‘ . 4900 1501 
Oxide of cape entge ; ’ 1-000 0°464 } 12-291. 
Potash, ; . 0-673 0-114 
Soda, ‘ ‘ ‘ = 0-438 0-112 
Water, + ..° 4 , > 0-200 0-177 § 
99-931 
The oxygen of the — is, 12-930 
ee 
' a Sh, gael en bases is, 12°291 
“From which it would seem that bibasic compounds are formed when 
the cement sets 
“*On comparing the analyses with each other, it appears that the chief 
constituents of the Connecticut cement are silica and lime, whereas a 
large proportion of magnesia enters into the composition of the Rosen- 
dale. The inference suggested by the results of the table is thus 
strengthened by those of the analyses, viz. that the increased energy of 
the latter cement may be ascribed to the formation of double silicates. 
“Dr. Jackson, who has performed many experiments with hydraulic 
mixtures, informs me, that the oxide of manganese will answer the same 
* The sand is not in chemical combination, but is ines: mixed with the 
other ingredients of the cement. 
