70 Improvements in Physical Science [Jan. 
mineral from Baumgarten, in Silesia. Its characters as he has de- 
scribed them are as follows :— 
The fresh fracture is snow-white ; but by exposure to the atmos- 
phere, it becomes yellowish-white. 
Fracture fine-grained uneven ; sometimes passing into the splin- 
tery and the even. 
Fragments irregular and sharp edged. 
Lustre dull. None is produced by rubbing the mineral with the 
nail. 
Slightly translucent on the edges. 
Very difficultly frangible. 
Scratches fluor spar and glass, and frequently gives slight sparks 
with steel. 
Does not adhere to the tongue. Sp. gr. 2°95. 
According to the analysis of Stromeyer, this mineral is com- 
posed of 
Magnesia ......-scccssescecres 4/°6334 
Carbonic acid ..... wie’, cielo damier Oey Osun 
Oxide of manganese ........++-. O°'2117 
Water, <.o.0-dauishantiaticd beids< estiale pean 
ooo 
100°0000 
Hence we see that this mineral is composed of an atom of mag- 
nesia united toan atom of carbonic acid. The water does not 
appear to be chemically combined with the carbonate of magnesia. 
(See Schweigger’s Journal, xiv. 1.) 
6. Anhydrite.—Stromeyer has likewise published the analysis of 
a variety of fibrous anhydrous sulphate of lime from Himmelsberge 
about half a German mile south-west of Ilefeld, where it occurs in 
a bed of the older floetz gypsum. Its constituents were, 
WaAG no ena she! oss eta erainte's e¥s-© clemrs sire. 40°673 
Sulphuric acid ~ 2... .4.---ceeecess 55°801 
Carbonic acid......... beacuse meet e 0°087 
Oxide. of trons acs oi sec boesa: secc> OF54 
Sili€a xsicedvess ie rka be dds sence OS? 
Bitumen: < saasa cess aes aa da othe -» 0°040 
Waters sscacesccss Si araitihic 3 Gsrenathe . 2914 
Golmmon: salt « ¢ssiieie tse s esd eee es Trace 
100°000 
Or it contains, 
Anhydrous sulphate of lime ........ 85°877 
Hydrous sulphate of lime ....... » ++ 137400 
Carbonate of lime: sc665:5 cies oe sens , O198 
CEE OGIOB eS 5.0 00d eleteln os 10:9 Bi0.b bs 0°525 
100°000 
(See Schweigger’s Journal, xiv. 375.) 
6. Gehlenite.—This is a name given by the Germans to a mineral 
described and analyzed by Professor Fuchs, in Schweigger’s Journ. 
