BURRELL : COMPOSITION OF SPAR IN MOTHER SHIPTON's CAVE. 285 
Calcium Carbonate. Small pieces are quarried from time to time by 
the lessee of the Mother Shipton Inn, and sold as deposit from the 
water. This is somewhat misleading, as visitors naturally expect it 
to be the deposit from the Dropping Well water. The spar is 
crystalline, of a rich brown colour, very hard, and takes a fine polish. 
100 parts of the air-dried spar contain : — * 
Silica (SiO.,) 
0-037 
Phosphoric Acid (P2O5) • • 
0-005 
Sulphuric Acid (SO.,) 
2-331 
Carbonic Acid (CO2) 
42-170 
Calcium Oxide (CaO) 
. 55-038 
Magnesium Oxide (MgO) 
0-190 
Strontium Oxide (SrO) ... 
0-128 
Manganic Oxide (Mn.j04) 
0-019 
Ferric Oxide (Fe,0,) 
0-006 
Alkalies, etc. 
traces. 
ponsti til puts mav be combined a 
s follows ; — 
Silica 
0-037 
Calcium Carbonate 
95-494 
Calcium Sulphate 
3-793 
Strontium Sulphate 
0-227 
Magnesium Carbonate 
0-397 
Oxide of Manganese 
0-019 
Ferric Phosphate... 
0.010 
Alkalies, kc. (by difF.) 
0-023 
100-000 
The spar is therefore mainly composed of Calcium Carbonate, 
with about three and three-quarters per cent, of Calcium Sulphate, 
and nearly one quarter per cent, of Strontium Sulphate. 
*" The atomic weights used are those given in Clowes & Coleman's 
Quantitative Analysis, 1894. 
