42 METHOD OF COLOURING KRIS BLADES. 
iron to cast iron, in a solution of arsenic in citric acid. Six qualities of 
iron were tested, with the result that they were found to bear the 
following relation the one to the other, each metal being so placed that it is 
electro-positive to all beneath it and electro-negative to all above it :— 
Cqstiron +. ~» small casting. 
Hoop iron. 
‘** ? Best thin sheet iron. 
{Ci steel, from an American axe. 
Wrought iron 
Steel Clock-spring steel. 
File steel. 
From what has already been said, it will be evident that if a blade 
were forged of strips of, say, clock-spring steel and file steel, and were 
then placed in a solution of arsenic, those portions of it which were 
formed of the file steel would darken, while the remainder of it would 
remain white. There is evidently something besides the proportion of 
carbon in combination with the iron which governs the galvanic relation- 
ship of this group of metals, but it would require a large series of 
samples, of which the constituents were known, to enable the influence 
of the carbon and other substances to be exactly determined. However, 
for the purposes of this inquiry it is sufficient to know that the difference 
of electrical properties in various qualities of steel suffices to determine 
the deposition of the coloured film, and that a homogeneous blade, not 
giving rise to any electrical currents, with consequent differences of 
chemical action, colours uniformly. 
A slight evolution of gas takes place during the process, and as a 
certain amount of it is arsenited hydrogen (an excessively virulent 
poison), every care should be taken in experimenting with this method 
of colouring damasked steel, to avoid inhaling the gas. 
The blade of the weapon to be coloured is first cleaned from any 
oil that may be on it with a little wood-ash and water, then a lime is 
taken and the rind carefully cut off, to prevent the oil from the outer 
skin getting on to the blade and interfering with the subsequent 
operations. The peeled lime is cut open and the juice rubbed over the 
blade with the fingers. From time to time it is washed in water and 
fresh lime-juice put on. This is continued until the blade is clean and 
white all over. Spots of rust which resist the acid are cleaned off by 
friction with a piece of charcoal. Powdered charcoal mixed with the 
lime-juice hastens the cleaning very considerably, and for this purpose 
that prepared from the rind of the durian fruit is preferred. 
The preliminary cleaning is also done by steeping the blade in 
either boiled rice and water, lime-juice, or chopped pine-apple leaves 
and water. About two days is required to free it from rust. The rice- 
water is said to be the quickest. The acid, of course, in this instance, is 
that formed by fermentation. A trough made of a joint of bamboo split 
longitudinally, or one formed with a piece of uwpzs—r.e., the spathe of 
the betel-nut palm, is used to steep the weapons in. 
A new blade is generally steeped for some days in one of the above 
acid fluids to etch it and bring the damask into relief. Seven or more days 
may be required for this purpose. It is usual to coat the edges of the 
