172 L. CASELLA'S CATALOGUE 



1993. Head of Hair, shewing that bodies similarly electrified repel each other 



(fg. 1993), p. 171 030 



1994. INDUCTION CONDUCTOB, with insulated stand and two pith balls 076 



1995. FIVE SPIBALS, with coloured glass tubes and revolving centre 1 4s. to 1 10 



1996. JOINTED DISCHABGEBS, with brass arms and insulated glass handles, 7s. 6d. to 



12 6 



1997. SMALL DISCHAEGEES, not jointed, with glass handles . . 026 



1998. AMALGAM, per box . . . . . 010 



1999. PITH FIGUEES, Is. each ; pith balls, per dozen . . . 009 



2000. PITH BALL STAND, illustrating electrical attraction and repulsion 036 



2002. Pith Image Plates, with brass stands . . . 086 



2003. THTJNDEE HOUSE AND POWDEE HOUSE COMBINED, for illustrating the use of 



lightning conductors , , . . . 150 



2004. THUNDEE HOUSE, for showing the use of lightning conductors 056 



2005. STUEGEON'S APPABATUS, for igniting gunpowder, alcohol, ether, etc., by 



electricity , , . . . . . 086 



2006. LUMINOUS NAMES OE WOEDS, on glass plates, with pieces of tin foil. May be 



rendered luminous in the dark by means of electric light, 7s. 6d. to 10 6 



2007. Two GLASS ELECTEICAL JABS, one of them belted and supported on a glass 



insulated pillar. This apparatus was employed by Franklin for the analysis 

 of the principles of the Leyden jar . . . 10 6 to 18 



2008. TIN FOIL, per roll , . . . . - 020 



2009. Mahogany Model of an Obelisk, to illustrate the properties of lightning 



conductors . ,- . , . .066 to 11 



2010. BALLOONS OF GOLDBEATEES' SKIN, they readily ascend when filled with or- 



dinary gas, 9-inch., Is. ; 10-inch., 2s. 3d. ; 12-inch., 2s. 9d. ; 16-inch. 036 



2012. BALLOONS, pear or fish shape. 5s. 6d., and upwards. 



2013. TATE'S BOOK ON ELECTBICITY . .009 



MAGNETIC AND ELECTRO-MAGNETIC INSTRUMENTS 

 AND APPARATUS. 



Instruments classed under the foregoing head are employed to exhibit magnetic 

 phenomena, whether produced naturally or artificially; but more especially their 

 relation in respect to each other, their reciprocal action and the direction they assume 

 when freely suspended. 



2014. Magnetic Steel Needles, of various lengths and forms, with central hard metal 

 caps for suspending on pointed stands, for illustrating the influence of terres- 

 trial magnetism as to the horizontal directive force, and the polarity of a 

 magnetic body, by its attractive and repulsive qualities in relation to similar 

 and dissimilar poles (fg. 2014), p. 175, 5s., 7s. 6d., 10s., and 15 



