Notices and Extracts from the Minutes of the Geological Societi/. 489 



The bones were found in the coal itself, forming layers about 2 inches 

 thick. They were for the most part so much shattered that the genus of the 

 animal could not be determined^, but from their great number they appear to 

 have been derived from many animals. After long-continued search a jaw- 

 bone with teeth was discovered, and from the inspection of a drawing of it 

 sent with the paper, Mr. Clift considers that it belonged to a hyaena. This 

 specimen is preserved at the Joanneum. 



Bones were first found in this mine in the year 1826, in the Joseph adit, 

 fifty fathoms from its mouth. They have been often met with since, in the 

 same adit; and in 1831 bones were also discovered in the Caroline adit of 

 the same mine. Among them was a tooth like that of a shark, together with 

 fragments of bones similar to those from the Joseph adit ; but they were 

 principally found in the strata adjacent to the coal. 



5. — Notice of a Machine for regulating High Temperatures, invented hy the 

 late Sir James Hall, Bart., F.G.S. : drawn up by Captain Basil Hall, Il.N., 

 F.G.S. &c. [Read May 1st, 1833.] 



Sir James Hall, in his experiments on the fusion of granite and other 

 rocks, and on the effects subsequently produced upon the fused mass by gra- 

 dual cooling, conceived that the experimenter required the power of regu- 

 lating the temperature in such a manner as best to imitate nature; and for 

 this purpose he invented the machine described by Captain Basil Hall. 



The principle of the machine is such, that when any change of tempera- 

 ture takes place in that part of the furnace in which the material under ex- 

 periment is placed, a corresponding change is made in the current of air 

 which maintains the heat. 



The furnace was about 3 feet long, 18 inches wide, and 2^ feet deep. 

 From side to side extended a muffle, one end of which was closed with a 

 plug, furnished with a small disk of mica, through which the subject of the 

 experiment could be viewed ; and at the opposite end of the muffle was 

 placed the machine. 



This instrument consists of a spiral spring coiled in a vertical plane, and 

 facing the muffle. The spring is formed on the principle of Harrison's balance 

 in chronometers, of two metals joined together, but of difterent degrees of 

 expansibility, so that the spring will either curl or uncurl, according as the 

 heat is raised or depressed. The outer part of the coil is fixed, while the inner 

 end is united to an axle, which, being free, turns round as the spiral winds 



