Hay.—Lime as Manure. 209 
The quantity of lime used per acre of necessity varies with the soil, and 
the expense with which it is procured. The heavy clay and peat soils 
require the largest proportions; the light lands need a much smaller 
quantity to produce the maximum benefit. The proportion commonly used 
on the clay soils in the midland counties of England is 100 bushels per 
acre; and 25 bushels per acre on light soils. In Scotland they apply 
sometimes as much as 860 bushels per acre; in Ireland much larger 
quantities are successfully employed; and on some of the peat mosses in the 
North of England more than 1,000 bushels have been used with good effect ; 
but, however, the employment of such large quantities can rarely be 
justified. 
ArT. XVI.—Notes on Quartz Crushing at the Thames.* 
By J. Gooparr, C.E. 
[Read before the Auckland Institute, 27th November, 1876.] 
I nave recounted on a prior occasion the chief errors of quartz crushing 
as practised on the Thames. I shall now endeavour to show how a great 
many of them may be avoided even by mechanical means of manipulation, 
that is without using chemical re-agents. Battery managers in general 
know too little of chemistry to look with favour on any process of gold 
. saving dependent on chemical means. 
That a vast amount of gold is lost yearly all over the world for want of 
proper means of saving it, is only too evident from the accounts contained 
in all metallurgical books recently published that treat on gold. It has been 
ascertained that 50, 60, and 70 per cent. are common losses. "That even 
‘this has been exceeded on the Thames, a case that came under my notice 
fully proved. The directors of the “ Golden Crown" mine, which at the 
time I speak of was a large producer, were desirous of ascertaining the 
relative merits of two rival batteries, so as to get their quartz erushed at 
the better establishment. To accomplish this they sent 50 tons of quartz 
to each mill. Special care was taken that the loads from the tip were sent 
alternately to each place, so as to equalize the quality of the quartz as 
much as possible. In the one battery, as well as I can now recollect, the 
uartz was crushed with quicksilver in the boxes, passed over quicksilver 
plates, then through Chilian mills, then over short blanket strakes. The 
blanketings and what remained in the Chilian mills were then passed 
through the amalgamating barrel. The total product of the 50 tons at 
that battery was less than 25 ounces, or under one-half ounce to the ton. 
* For previous Paper by Author see ** Trans. N. Z. Inst.," Vol. VIIL, p. 176. 
al 
