STUDIO AND WORKROOM 2 
glycerine and finely powdered litharge may be worked into 
a thick paste; the broken edges should be painted with 
glycerine, then the paste applied, and the articles bound to- 
gether with string and left for a day or two. Or zinc oxide 
should be worked into a stiff paste with a 15 per cent solution 
of zinc chloride. Or: 
Sulphur flowers 72 parts 
Pale resin 40 parts 
Shellac 10 parts 
Mastic 20 parts 
Crude lac 20 parts 
Barium sulphate 60 parts 
Melt the gums by heat and add the sulphur, stir well and then 
add the baryta. This must be melted each time before use. 
DIAMOND CEMENT.—Dissolve gelatine to saturation in 
glacial acetic acid. This must be melted on a water bath 
before use. 
DAMP-PROOF GLUE.—Cover some good glue with water 
and allow to soak for 12 hours, drain off the water, melt the 
glue by heat, and add one-fourth its volume of linseed oil. 
MarInE GLuE.—Dissolve india rubber shreds in benzole 
1 part, shellac 2 parts; or ordinary cycle tyre cement may be 
used, one-fourth its volume of shellac added, and melted by 
heat. The vapour of this is very inflammable. 
Lioguip GLuE—This should not be used for mounting 
photographs : 
Fine glue 800 g 8 02. 
Water 1000 cem 10 oz. 
Allow to soak for 24 hours, then melt by heat, and add: 
Nitric acid, strong 175 ccm 134 oz. 
SILVERING GLass.—Brashear’s Process modified, as used 
at the Royal Observatory, Greenwich, England. The follow- 
