STUDIO AND WORKROOM 5 
Clean the metal thoroughly, immerse in the mixture, and then 
heat; repeat if necessary. Or the following may be used: 
Copper carbonate 50 g 384 gr. 
Ammonia 25 ccm 192 min. 
Water 1000 ccm 16 oz. 
Clean the metal and immerse until black, then wipe dry and 
lacquer. This attacks soft solder. Solution of antimony 
(butter of antimony), brushed on, gives bronze colours. It ’ 
has been stated that boiling the metal in a solution of potas- 
sium sulphide (liver of sulphur) until sufficiently black, then 
rinsing, drying and smearing a little oil over it, gives better 
results than the above silver method. 
FIREPROOFING FABRICS.—Soak in: 
Alum 80g 7 8 oz. 
Ammonium carbonate 25) 3 24 02. 
Boric acid es 1Y, oz. 
Borax 1758 134 oz. 
Water 1000 ccm 100 oz. 
Or: 
Boric acid ie 200 gr. 
Ammonium phosphate 100 g 4 oz. 
Water — 1000 ccm AO oz. 
Or: 
Borax 150 ¢ tZloz. 
Magnesium sulphate PSs 9 oz. 
Water 1000 ccm 80 oz. 
Starch PASS 2/Oz. 
Boil the starch with the water and add the salts. Immerse 
the fabric until thoroughly soaked, then dry and iron. Ora 
strong. solution of aluminum acetate, sp. gr. 1.050, diluted 
with 40 times its volume of water, may be used. The material 
should be immersed for 24 hours and then dried in the shade. 
