TRANSACTIONS OF SECTION B. 37a 
alkali, below which the amount of zine dissolved is insignificant, being little 
greater than that due to the solubility of zinc hydrate in pure water. In addition, 
the author has succeeded in showing that the experimental results can be deduced 
from the ordinary assumptions of the ionic theory, and, in particular, that the 
results given by caustic potash are the same as those given by caustic soda when 
expressed in gram molecules ; so that it follows that the solubility of zine hydrate 
in alkali depends solely on the concentration of hydroxidion in the solution. 
It was also shown that no definite chemical compounds (such as ZnO.8KOH) 
exist, since the curve obtained by plotting the results is approximately a parabola, 
and its tangent never passes through the origin. 
A practical result of the investigation is to show that in working cyanide 
solutions scarcely any of the zinc is present as zincate, but nearly all is zinco- 
cyanide. 
2. The Functions of the Metallurgical Laboratory. 
By Gerarp W. WILLIAMS. 
The subject of the paper was dealt with under four heads :— 
(a) The laboratory in regard to metallurgical research. 
(6) The laboratory as a testing department for mine supplies, 
(c) Personnel and educational training of the staff. 
(d) Equipment. 
(a) The utility of the laboratory to metallurgical research is based on the rela- 
tive value of small-scale experiments to the working processes they are designed 
to illustrate. 
In general it may be said that all processes, the fundamental principle of 
which lies in the inter-reaction of two or more bodies, can be tested with accuracy 
in the laboratory. 
Subject to the laws of mass action, the reaction which takes place in a test 
tube will take place equally on a working scale. The author on one occasion con- 
ducted a lengthy series of tests on the extraction obtainable from banket ores under 
different conditions as to crushing. The results obtained by bottle tests were 
completely borne out in actual practice. 
Questions involving mass‘action, slow oxidation, and physico-chemical changes 
are less easily studied in the laboratory, but considerable accuracy is possible. 
Other instances of actual improvements introduced as a result of small-scale 
experiments were quoted, and stress was laid on the importance to the mining 
industry of the Witwatersrand of the establishment of a fully equipped labora- 
tory fitted with a ten-stamp battery and all necessary plant. 
The full effect of any modification in working conditions would be noted, as 
it would not be obscured by other issues. Similar experimental plants are to be 
found in all the important gold-mining centres of the English-speaking world. 
(6) The importance of the testing of all mine supplies is obvious. This is done 
in all large European and American works. The twentieth century might well be 
called the age of adulterants. To such a pitch has this practice been carried that 
all large firms, home and Transatlantic, now buy all supplies on contract speci- 
fication only. There is great need in this country for such a department. The 
author quoted instances of adulteration of supplies which have come before him, 
and showed how high prices are frequently paid for worthless and even harmful 
goods ; coal, lime, cyanide, and all mine supplies of a similar nature may be tested 
and bought on true value only. This involves a direct saving more than equivalent 
to the expenses of the department. The analysis of boiler-feed waters, flue gases, 
and the conducting of full boiler tests, furnishes information of great value to the 
engineer. 
The advantages of the metallurgical laboratory from this standpoint are obvious, 
in that the results have an immediate cash value, and were the laboratory to 
accomplish nothing else, its value to the industry would be assured. 
BB2 
