April 1, 1909 
made must be diluted largely before the 
lime solution is added to it. This is a 
very important point. If the copper 
solution is too strong, the precipitate 
formed is thick and heavy, and liable to 
If the 
- copper solution is made by dissolving the 
bluestone in a small quautity of hot 
water, it should be diluted to 20 gallons 
before adding the lime. 
— Lime— 
The lime, which should be freshly 
burnt, is slaked with a small quantity of 
Sl king on a board is recom- 
clog the nozzle of the spray-pump. 
water. 
~ mended rather than in a cask, because if 
the lime is really freshly burnt there will 
be considerable heat evolvei, and the 
barrel may suffer, Place the whole of the 
lime on a board, and pour over it 3 or 4 
pints of water, The lime, if it is good 
- should become very hot, crack asunder, give 
off a quantity of steam, and_ finally 
crumble inio a fine white powder, This 
is now emptied into a barrel and water 
added. 
the whole of the lime into a wash. It 
cannot be done by simply stirring about 
with a stick. The best way is to use a 
shallow tub, so that the lime may be 
pounded up with the water, all the lumps 
being broken up. Allow to settle, and 
pour off the milky solution through a 
strainer if any lumps are present (into the 
copper sulphate if you like, or into 
another barrel), and add more water, re- 
peating the pounding until all the lumps 
It is not an easy matter to make 
have disappeared. 
—Mixing.— 
The mixture must be made by pouring 
the lime-water into the copper solution 
-and not by adding the copper solution to 
the lime-water. 
—Th» proportions of the Ingredients, — 
The proportions above given provide 
ample lime to more than neutralise all the 
copper sulphate; in fact, there is more 
than twic; the quantity required to 
convert the copper into the dydrate, pro- 
vided, firstly, that the lime is pure; 
secondly that it is freshly burnt, and 
thirdly, that the lime is really all made 
into wash. 
With regard to the latter point, in- 
structions are often disregarded, and in 
‘many cases not more than a quarter or 
THE AUSTRALIAN GARDENER. 
half the quantity of lime recommended 
becomes * finally the 
copper. 
Tf, in addition to this, the lime is not 
pure, and has been burnt some time be- 
fore being used, it may easily happen that 
instead of the above quantities of lime 
being in excess of what is required, they 
may be altogether insufficient for the 
purpose, and that the solution may con-’ 
tain fres copper sulphate. 
combined with 
free copper sulphate, even in small 
quantities, does ‘burn’ the foliage, and 
that it is undesirable to have any ia the 
mixture on this account, it app3ars pre- 
ferable to have no fixed quantity of 
lime, but simply to have a definite 
quantity of copper, and to add the lime 
This is 
plan recommended in the latest 
Bulletins of the United States Depart 
ment, and is described in detail by Dr. 
Cobb in the Agricultural Gazette, April 
1897. 
In order to know when the copper 
sulphate is destroyed, the rerdiesé test is 
ferrocyanide of potassium; but if is im- 
portant to remember that at a certain 
until the copper is neutralised, 
tne 
point ferrocyanide ceases to give the 
characteristic colouration (in such a 
solution as we are dealing with), although 
there is still unaltered copper sulphate in 
solution. In other words, the solution 
may contain free sulphate of copper, al- 
though the ferrocyanide test, applied as 
directed, does not show it. Therefore it 
is important to remember that the mix- 
ture is not ready for use when ferrocyanide 
no longer gives a red colour, but that a 
quantity more lime {even half as much 
again) must be added. 
Instead of ferrocyanide, a rough test to 
show when sufficient lime has been added 
consists in placing a clean knife-blade in 
If there 
is no red stain on the knife-blade, the 
When 
this point is reached, addsome more 
lime. 
the mixture for a few minutes. 
copper solution is neutralised. 
—Vessels Employed.— 
For the copper solution, wooden vessels 
are prefetablo, though copper vessels may 
be used.. Iron vessels should be avoided. 
For the lime, wooden tubs or barrels, Do 
not leave the mixture in the spray-pump 
Assuming that - 
23 
as it will slowly attack the copper; but 
when the spraying is finished, pour it 
away and wash the pump and hose well 
with water. 
—Purity of Ingredients, — 
Sample of ‘oluestone’ are often received 
_which contain a quantity of sulphate of 
iron. This adulteration can only be 
effected by dissolving copper sulphate and 
sulphate of iron, mixing the solutions, and 
Such a 
method is much too elaborate to be carried 
out on a small scale, and there must be 
more of the stuff about. The following 
hints will enable any one to suspect such 
acompound. Bluestone should be in the 
form of dark-blue crystals (the adulterated 
mixture referred to is light-blue, like sul- 
phate of iron). They dissolve completely 
in water—readily and completely in hot 
water or water to which any acid is 
added. 
In order to test its purity still further 
add ammonia. 
allowing them to crystallise out. 
A pale-blue precipitate is 
formed, which dissolves to an intense 
blue colour. This solution should be 
perfectly clear, and leave no sediment on 
standing If a reddish sediment settles, it 
is due to ths presence of iron. 
Lime:—The best freshly-burnt stone 
lime only should be used. ‘To test 
it, placa a few lumps in a small heap and 
sprinkle with water. The water should 
be absorbed by the lime, when the latter 
gradually falls to pieces, becoming very 
hot in the process, and given offa quan- 
tity of steam. It gradually crumbles to 
a fine, white powder. Ifit does not get 
hot enough to give off steain, it has not 
been freshly burnt. 
Yhe addition of molasses has been 
advantageous in the preparation of 
Bordeaux mixture. Mollasses helps’ the 
mixture to stick to the foliage, and by its 
addition saccharate of lime is formed, so 
that it is easier to get a proper solution 
which will not choke the nozzles. ; 
If molasses is used the proportion will 
e— 
Bluestone noes ee OP LD: 
Lime ii So Sales, 
Molasses m - 4 quarts 
made up to 22 (for winter) or 40 gallons 
(for summer) with water, 
—The Damage done—  . 
The amount of damage done by this 
disease is variously estimated, but is, on 
the whole, perhaps exaggerated. Accord- 
ing to the observations of Dr, Gobb, it 
causes much less loss than Melanose 
though in some orchards the Black 
Spot predominate, and in such is respon- 
sible-for much damage. 
—Victorian “ Journal of Agriculture.” 
