Paints ', Stains, Varnishes 139 



Fusible metal composed of 



40 parts by weight of bismuth. 

 20 ., lead. 

 10 tin. 



10 cadmium 



15 mercury. 



is said to cement glass securely to metal, as also will some 

 solders, particularly the one recommended for aluminium. 



It is sometimes of advantage to have a wax for the 

 temporary attachment of indicating needles of straw or paper, 

 and this wax should be sufficiently soft to admit of squeezing 

 into any desired shape, and should easily and firmly adhere to 

 any material upon which it is pressed. Waxes of this kind 

 are easily made by mixing in suitable proportions various 

 hydrocarbons belonging to the same class paraffin wax, 

 vaseline and paraffin oil, for example. A few trials will soon 

 enable any one to mix up a wax suitable for his particular 

 purpose, and this more easily by trial than by weighing out 

 definite quantities. 



IX. PAINTS, STAINS, VARNISHES. 



Paints. Only one or two of these need be mentioned. 

 Laboratory stands, of wood, are frequently painted black with 

 a mixture of lampblack and shellac varnish. The saturated 

 shellac varnish is diluted to about half strength with methylated 

 spirit, and is used to mix with a quantity of lampblack while 

 this is being ground in a mortar. When perfectly fine the 

 ground lampblack is mixed into the shellac and spirit solution 

 until an opaque dead black coating is obtainable at a single 

 application. The mixture is kept well stirred while being used. 



A white enamel is made by mixing 3^ Ibs. of white lead, 

 ground in oil, with half a pint of " inside " oak varnish, and 

 stirring well. It must be kept well stoppered when not in 

 use. This will be found quite satisfactory for painting numbers 

 upon benches, etc. 



