104 



EECBEATIVE SCIENCE. 



be easily comprehended by referring to the 

 accompanying diagram. 



Tlie oblong figure represents a common 

 slate, which, may be suspended from nails in 

 a wall by the rings g h. The bar extend- 

 ing from A to c is a copper wire, about one- 

 tenth of an inch thick, fixed to the slate at 

 A, but free to move in the direction of its 

 length at c. The pointer, c f, has a notch 



in it at c, on the side towards a, and moves 

 freely on a fulcrum, d (a well-rounded piece 

 of metal, securely fixed in the slate, to fit a 

 small hole in the pointer, c f, at x>), about 

 one-tenth of an inch below the notch. The 

 weight of the index keeps the wire a c 

 (which is filed to a sharp edge at the end c 

 to fit the notch) against the notch. 



If A c be lengthened, it will obviously 

 (a being fixed) cause the index c f to move 

 upwards on the graduated arc at f. Apply 

 a lucifer taper to the copper wire, say at b, 

 and the index will at once move upwards. 

 Remove it, and, as the metal cools, it Avill 

 gradually fall. The experiment is a very 

 simple one, and illustrates the subject in a 

 very pleasing manner. The dimensions of 

 the instrument may be considered as ad 

 libitum; but a convenient size will be as 

 follows : — A c = 1 foot ; c D {i. e., from the 

 notch to the fulcrum) = tV of an inch; 

 D F = 10 inches. For every hundredth of 

 an inch movement of the radius c d, f will 

 move an inch — an amount soon obtained by 

 applying the taper as above. 



The instrument is simply designed to 

 shoto the expansion and contraction of the 

 copper wire, not to measure it accurately. 

 The one constructed by the writer is suffi- 

 ciently sensible to show a difference in the 

 length of the wire by the alteration of the 

 temperature of the air in a room, at different 

 periods of the year, and by a slight calcula- 

 tion may be made to answer the purpose of 

 a thermometer (in some degree), although 

 an indifferent one. 



WlLLIAK C. BUEDEE. 



Observatory, Clifton, Bristol, 



PHEENOLOGY IN THE POULTRY- YAED. 



►SHi' 



That the brain is tha organ of the mind, and 

 the ultimate means by which it is brought into 

 relation with the material objects around us, 

 is a fact admitted by all persons who have 

 bestowed a thought upon the subject. Phre- 

 nologists, however, take a step in advance of 

 this position, and map out the brain into 

 certain regions, asserting that the different 



parts have distinct functions to perform ; for 

 instance, that one part is concerned in the 

 perception of colour, a second with that of 

 size, a third with that of form, and so on ; 

 and that the higher or reasoning faculties are 

 situated in a distinct part of the brain from 

 those which are concerned in the perception 

 of external objects, and that both these pro- 



