RF eT rod FE GIRS PRN Sa SES, oe a re Ce ML Eon A ees woe te Neh SLL GN gy Cs as a ee ee RSS ae ot oie ye SS a Stel Ro A ae Re oi oe ie ee ee ee eee ee Rs bur Omer Lk Sk bl aues 
ee 
IN THE NEW BRITAIN GROUP. 87- 
We have now to consider its chemical composition in some- 
ers mse ae and to cokes the results furnished by it on 
h those yielded by specimens of typical or true 
Chemical Composition of Specimen from New Ireland. 
Hygroscopic moisture, @.e., water driven 
off it, 100° C 1:202 
’ Carbonic anhydride Ee .. 35°337 
Tron sesquioxide... an ves a 
Alumina ... bes vs on 8 131 
Silica ms sis 7-933 
Phosphoric acid . te Minute tut 
eo protoxie i a “62 
Lim vais — 45°278 
Magnesia. wen mn ar te “476 
Potash ions <a none i “B08 
Chlori a i. 
Combined water and loss. ne a= ee 
100°000 
geste gravity, 2°199 at 59° F. 
e specifi vity was taken from a mass weighing about 73 
grammes, which was allowed to soak in water for about one hour 
and a half, in until all air bubbles ceased to evolved ; a 
small quantity of the block mapa off when immersed in the 
water—a correction for which had t 
1e abov ires show that in acter mbers about 81 per 
cent. of the specimen consists of caleium pack onate ; thus it is 
undoubtedly a far less: pure limestone than the ordinary white 
chalk, as the following figures indicate :-— 
Chemical Composition of Chalk from other Places. 
A specimen of chalk, from near Gravesend, — was ro 
by Mr. W. J. Ward, yi ielded the following results 
Calcium carbonate... ne es 98: “52 
Magnesium carbonate .. : fae ‘29 
Calcium sulphate i at vat "14° 
Manganese binoxide ... ats = 04 
a oh ot i -«- traces 
Racdalioon cna hte chiefly silica we 
