38 GAUSS AND WEBER ON TERRESTRIAL MAGNETISM. 



it might not conceal the stiniip situated behind it, and is repre- 

 sented by itself in fig. 4. In the westerly view, fig. 3., the small 

 notch in the stirrup into which the weight-carrier fits, is merely 

 indicated; while in the southern view, fig. 6., it is shown as fitted 

 into the notch, and placed on the magnet bar, and the two half 

 kilogrammes it is to bear are suspended from its points. 



Fig. 1. presents a view of the suspender, with the screw and 

 suspension thread, from the west. A A i^ a board fixed to the 

 ceiling ; B B two parallel wooden rods glued to it, between which 

 a slider, D D, may be moved from east to west ; it is supported 

 by two projecting parts, C C; the brass nut, E, through which the 

 elevating screw passes in a direction from east to west, is fixed 

 with screws to the slider ; F is the screw head at the western 

 extremity, which in this figure hides the screw ; G is the suspen- 

 sion thread attached to the screw. 



Fig. 2. represents a view from the south, of the same suspender, 

 with the screw and thread. A A here, is the longitucUnal section 

 of the board fixed to the eeiUng ; B B is the rod glued to this 

 board on the north side ; C C the support of the slider ; it is fur- 

 nished at the edge with a scale, for the adjustment of the slider; 

 D D the longituchnal view of the slider, to which the copper nuts 

 E and E' are fixed with screws. Through these nuts passes the 

 elevating screw, the head of which is represented by F. This 

 screw passes through the nut E, and is kept in its place by the 

 nut H. Near to the second nut E' the screw changes into a 

 smooth cylinder which passes tlu-ough a smooth aperture of the 

 nut E\ At the end of the thread of the screw the suspension 

 thread G is fastened, and hes in the grooves, in which it continues 

 to the centi'e, and there falls perpendicularly, bearing at its lower 

 end the stirrup of the magnetometer. When the thread is to be 

 raised, the nut H is loosened, and the screw turned by the screw- 

 head F into the required position. 



Fig. 3. presents a view, fi'om the west, of the vibrating portion 

 of the magnetometer. It consists of two eyes, A A, of which 

 the posterior is concealed in this figure by the anterior. The 

 lower end of the thread G is fastened to a pin fixed under them. 

 To this part of the magnetometer belongs also the torsion-circle 

 B B, upon which the stirrup C C C C rests ; the magnet bar 

 D D, and the mirror-holder E, with two fi-ames FF, HH, and the 

 clamps KK, serving to receive the mirror. With the exception 

 of the magnet bar, which alone weighs 1700 grammes, and of 



