174 . L. CASE;LLA'S CATALOGUE 



2023. MAGNETIC TOTS, consisting of floating swans, ducks, fishes, ships, mermaids, 



etc., showing magnetic attraction and repulsion, each 6 to 5 



2024. Pith Figures of Men and Women, with a soft iron wire passed vertically 



through the centre of the figure, to illustrate in a pleasing manner magnetic 

 attraction . . . . . . 2 6 to 5 



2025. ASSORTMENT or MAGNETIC APPAEATUS, i.e., permanent steel magnets, to show 



attraction and repulsion. Soft iron balls, rings, cylindrical rods, swans and 

 fishes, to illustrate the action of the magnet on ferruginous bodies. Horizontal 

 and dipping needles, to exhibit their magnetic directive polarity and inclina- 

 tion or dip. With this apparatus many interesting experiments may be 

 performed to elucidate the facts in magnetic science 2 2 to 3 3 



2026. APPAEATUS TO ILLTJSTBATE BAELOW'S MAGNETIC COMPENSATOE, for neutralizing 



the eifect of local attraction on the ship's compass. Consists of a magnetic 

 compass with a piece of soft iron placed so as to represent the guns, anchors, 

 cables, etc., with another mass of iron to compensate for the derangement of 

 the compass produced by the iron in the vessel 3 3 to 5 5 



2027. IMATUBAL LOADSTONE, mounted in soft iron cheeks for concentrating its power, 



with soft iron armature for increasing its lifting power, and to preserve its 

 magnetic properties . ' . . . . 3 3 to 5 



2028. SLICED PIECES or LOADSTONE OB NATUEAL MAGNET . 1 6 to 7 6 



BAR MAGNETS, 



Adapted for the experimental elucidation of .that property conferred on bodies 

 composed of iron, whereby, under certain conditions, they acquire the powers of polarity, 

 attraction of unmagnetic iron, attraction and repulsion of magnetic iron, and the 

 influence of inducing magnetism in other iron not previously magnetic. 



2029. Bar Magnets^ strongly magnetized, of the best steel, in boxes, per pair, 6 inches 



long, 2s. 6d. ; 7 inches long, 3s. 6d. ; 8 inches long . .. 046 



2030. BAB MAGNETS, of cylindrical steel, for sustaining rotating apparatus, or revolving 



on their axis, or inserting within hollow wire coils to illustrate the elementary 

 experiments on magneto-electricity, 5s., 7s. 6d., 10s., and . 15 



2032. MAGAZINE OB BATTEBY or STBAIGHT BAB MAGNETS, united by screws; a 

 useful arrangement for impregnating other bars with the magnetic properties 



1 1 to 2 10 



Horse-shoe Magnets. In this form of the artificial magnet both poles are brought near 

 to e ach other, and the extremities being made smooth, the magnet acquires 

 an increased power of sustaining weights (fig. 2035), p. 175 : 



Long. Per dozen. , Long. Each. 



2033. 2i inch. . ' 026 



2034. 4 inch. . 066 



2035. 7 inch. . 120 



2036. 11 inch. . 046 



2037. 15 inch. . 070 



2038. 20 inch. 13 



