BAIRD &.TATLOCK (LOM)ON) LTD. 



6160 



6160 s Baird & Tatlock's Set of Blowpipe Apparatus, in varnished pine box. Outside 

 measurements, gf by 6f by 4 in. . . . . . . . . . . each 



CONTENTS. One hammer with chisel end, one grease lamp, one block compressed charcoal, one small agate 

 mortar in wooden block, one pestle for ditto with wooden handle, two porcelain crucibles, one piece platinum foil 

 - by i in., one 3-in. horseshoe magnet, one lens for magnifying, needle for cleaning blowpipe nozzle, one aluminium 



uljlimate plate, one pair nickel-plated forceps, six 6-in. lengths glass tubing, one Black's blowpipe, one tin spirit 



amp, one steel anvil, one hundred niters 2 J in., one box extra wick for spirit lamp, one piece platinum wire 4 in. 



ong, one pair cutting pliers, one book blue litmus paper, one pair forceps with platinum points, one zinc plate, 

 12 in. thin copper wire, twelve bulbs and arsenic tubes. Turned Wood Boxes containing Sodium carbonate, 



>orax, sulphur, copper oxide, microcosmic salt, fluor spar, lead grain. Bottles containing Phosphoric acid, 



obalt nitrate solution, potass bisulphate, boracic acid, tinfoil, 



160 



6161 



6161 (packed in iase) 



)161 S Prospector's Ivory Density Rule and Scale of Hardness, suitable for prospectors 

 or explorers. Price in japanned tin box ,with,divisions 



DESCRIPTION. 



The density rule is a very light and convenient little instrument, no larger than a pencil, that may be carried 

 n the pocket without inconveniencing the traveller, and together with the accompanying scale of hardness gives 

 iumcient data for the identification of a large number of minerals. 



To make a density determination, select a specimen somewhat over 10 grammes in weight ; place the brass 

 ob with the index marks at zero on the density and millimetre scales ; suspend the specimen by a horse-hair 

 r silk thread from the other arm, at any point where it will exactly counterpoise the bob, and fix it there, which 

 lay conveniently be done by having a running loop on the horse-hair. Now immerse the specimen in water, and 

 love the brass bob back until it again counterpoises the specimen. On the density scale the index of the bob will 

 how the density of the specimen, with accuracy to the first place of decimals for any ordinary specimen, from a 

 ensity of from 2 to 5. From 5 up to 10 it will read to half a unit, and thereafter it is only approximate. 



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