384 Scientific Intelligence — Geology. 



colour, hardness, specific gravity, &c. — being well accounted for by 

 the isomorphous replacement of alumina and peroxide of iron, and 

 protoxide of iron and zinc. This opinion is confirmed by the follow- 

 ing comparison of compositions, according to the analysis of automo- 

 lite by Eckeberg and Abich. 



Dysluite. Ox. Ratio. Automolite. Ox. Ratio. 



Alumina, . 30-49 14-23) o^.^. _ o Alumina, . 57-09 25-37 = 3 

 Perox. iron, 30-00 6-00/ ^^ ^-^ — "^ Oxide of zinc. 34-80] 

 Protox. iron, 11-93 2'Q6\ Magnesia, . 2-22 > 7'42 = 1 



Protox. mang, 7*60 1*68 > 7*53 = 1 Protox. iron, 4-55) 

 Oxide zinc, 16-80 3-20) Thomson. Abich and Eckeberg. 



To confirm this probable view, a new analysis of dysluite is required, 

 to shew the iron to be protoxide, as Dr Thomson (the only chemist 

 who has analysed this mineral) states it to be peroxide. — (American 

 Journal of Science and Arts, Vol. i., 2d Series, No. 1., p, 121.) 



GEOLOGY. 



24. M. A. Daubree on the High Temperature observed in a Pit 

 sunk at Neuffen, in Wurtemberg. — Of all the cases of increase of 

 temperature in deep excavations hitherto ascertained by means of 

 exact observation, the most rapid is that remarked by Count Man- 

 delslohe, in a pit sunk near NeufFen, in Wurtemberg. According 

 to the results given by him in Leonhard and Bronn's Jahrbuch for 

 1844, p. 440, the orifice of this pit is situated at a height of 1378 feet 

 (420 metres) above the level of the sea, and 1070 feet (326 metres) be- 

 low the plateau of the Alp of Wurtemberg, at the foot of which it is 

 situated. Its depth is 1263 feet (385 metres). The rocks in which it is 

 sunk consist, to a depth of 804 feet (245 metres) from the surface, of 

 bituminous black slates belonging to the inferior oolite ; but beyond 

 that depth, calcareous and marly beds of the lias are met with. The lat- 

 ter reach to the bottom of the pit, and, consequently, the beds of the 

 Keuper, which were the object of the excavation, have not been reached. 

 Observations were made, by means of Magnus' geothermometer, at 

 twelve points, between a depth of 98*5 feet (30 metres), and the 

 bottom, where the instrument indicated 101°-6 Fahr. (38°-7 Cent.). 

 The mean of all these observations, which harmonize very nearly, 

 gives an increase of 1^ Cent. = l°'8 Fahr. for 34-4 feet (10-5 me- 

 tres) of depth. This progression, which is at least three times more 

 rapid than that observed in most other countries, even exceeds, by 

 one degree Centigrade (l°-8 Fahr.) in 13 metres (42-6 feet) the pro- 

 gression observed at Monte Massi, in Tuscany, where the increase 

 was the greatest which has been well ascertained. The bottom of 

 the pit now under consideration is 114-8 feet (35 metres) above the 

 level of the sea. Without at present discussing the various other 

 circumstances, such as the presence of iron- pyrites in the slate, 

 which may have exercised a slight influence in producing this ano- 



