398 Meteorological Observations for March 182S. 



III. Tautolite. 

 pyramid. 



a:b:c = 1:1-9451 



Observed combinations : 



Prismatic. Fundamental form, scalene four-sided 

 1-3648. 



1, M 



f 



= ooa:£:c = 109°46'. 



= 4 a : b : oo c = 51° 52'. 

 i = <x a : oo 6 : c fig. 9 of Mohs's treatise, 



2, M;^;A; 

 i = oo a : | 6 : c = 86° 22'. 

 e=2<z:&ooc=88° 25'. 



M ;" 



Cleavage, only in traces and interrupted, parallel 

 toMand/j. Fracture conchoidal. . .uneven. Lustre 

 vitreous. Colour velvet-black. Streak gray. Opaque. Hardness 

 = 6-5. . .7*0. Sp. gr. = 3-865. Before the blowpipe, upon char- 

 coal, the tautolite melts to a blackish scoria, which is attracted by 

 the magnet ; with borax it melts to a clear green glass. These and 

 other reactions show that the mineral consists of silica, black prot- 

 oxide of iron, magnesia, and alumina. It is found in the volcanic 

 feldspath-rocks, in the neighbourhood of the Lake Laach Sea in 

 Rhein-Prussia. The tautolite seems to be related to the chrysolite, 

 as the Ceylanite to the Spinelle. — Brewster's Journal of Science. 



METEOROLOGICAL OBSERVATIONS FOR MARCH 1828. 



Gosport. — Numerical Results for the Month, 

 Barom. Max. 30-30 Mar. 16. Wind W.—Min. 29-02 Mar. 21. Wind S.W. 

 Range of the index 1*28. 



Mean barometrical pressure for the month 29-879 



Spaces described by the rising and falling of the mercury 5*640 



Greatest variation in 24 hours 0-580. — Number of changes 1 7. 

 Therm. Max. 63° on several days.— Min. 30° March 6. Wind NW. 

 Range 33°.— Mean temp, of exter. air 47°-92. For 30 days with in X 4972 

 Max. var. in 24 hours 23°-00— Mean temp, of spring water at 8 A.M. 50°-86 



De Luc's Whalebone Hygrometer. 

 Greatest humidity of the air in the morning and evening of the 16th 100° 

 Greatest dryness of the air in the afternoons of the 19th & 24th... 44 



Range of the index 56 



Mean at 2 P.M. 58°-4 —Mean at 8 A.M. 73°'0— Mean at 8 P.M. 71-4 



of three observations each day at 8, 2, and 8 o'clock 67*6 



Evaporation for the month 1*90 inch. 



Rain near ground 1-755 inch.— Rain 23 feet high 1-620 inch. 



Summary of the Weather. 

 A clear sky, 4£ ; fine, with various modifications of clouds, 15; an over- 

 cast sky without rain, 7a ; foggy 1 ; rain, 3. — Total 31 days. 

 Clouds. 

 Cirrus. Cirrocumulus. Cirrostratus. Stratus. Cumulus. Cumulostr. Nimbus. 

 12 6 24 1 19 25 15 



Scale of the prevailing Winds. 

 N. N.E. E. S.E. S. S.W. W. N.W. Days. 

 3* 2J 1 3 i 6 5i 9 31 



General 



