318 QUEENSLAND AGRICULTURAL JOURNAL. [lL Srpr., 1899. 
TO DETECT ADULTERATION OF SULPHATE OF COPPER. 
A FARMER'S TEST. 
Mr. S. A. Woopneap, B.Se., Lecturer on Chemistry at the Agricultural 
College, Uckfield, has devised a simple test for detecting adulteration of sulphate 
of copper. It requires no scientific knowledge to apply it, and the ordinary 
breakfast table supplies the necessary apparatus. Every year the use of sulphate 
of copper on the farm rapidly increases. Every farmer uses it to dress his seed- 
corn, to prevent smut and bunt. The practice of spraying potatoes to prevent 
potato disease is fast extending, and the success attending the spraying of crops, 
to destroy charlock, leads to the reasonable expectation that there will be large 
quantities used for this purpose. As sulphate of iron costs only about one- 
eighth of sulphate of copper, and as its substitution in part or altogether is a 
common fraud, it is very important that the farmer should have a ready means 
for detecting the fraud. The purchaser is not only defrauded in price, but the 
results he may look for on his crops are not realised. 
After the demonstration of charlock-destroying at the Agricultural College 
Farm, Uckfield, Mr. Strawson suggested to Mr. Woodhead the desirability of 
some simple test, and together they arrived at the one described below. Tron 
salts and tannin are employed in the manufacture of ink ; tea ae tannin. 
If a solution of tea be poured on a solution of sulphate of iron, the tea takes a 
black colour, and a flocculent precipitate quickly forms. When, however, the 
solution of sulphate of iron is substituted by sulphate of copper, the change is 
but little, and tends to a brown or dirty olive-green, which cannot be confounded 
with that from the iron salt. The test, therefore, can be done at the tea table. 
If a rather more accurate method of doing it is desired, make a solution of 
tea—one teaspoonful in half-a-pint of boiling water. Make another of one 
teaspoonful of the sulphate in half-a-pint of water. Then pour some clear 
water into a tumbler, and put in a teaspoonful of both the solutions. If there 
is iron in it, a black tinge will pervade the mixture. If it only becomes browner, 
or becomes a dirty olive-green, there is no iron present. If a comparative test 
is desired, make also a solution of known pure sulphate of copper—one tea- 
spoonful to half-a-pint of water. Take two tumblers, set them on a sheet of 
white paper side by side, partly fill with clear water, add tea until both are 
exactly the same colour. Then in one put the doubtful solution, and in the 
other the copper solution. The comparison is then very easy. If there is 5 
per cent. of iron in the doubtful solution, it will look like watered ink; but as 
little as 2 per cent., or even less, can easily be detected. With so simple and 
inexpensive a test, no farmer need suffer from the fraud he ix now very liable 
to.—Mark Lane Express. 
PRESERVING EGGS. 
Tu following two recipes came from Germany and France respectively. The 
Pharmaceutische Zeitung gives one by Professor Dietrich, who says :— 
Take 25 parts of sodium silicate with 75 parts of water. The water is to 
be first boiled and then cooled before using. Well water is recommended. 
The white of eggs so preserved will, he says, beat into a good froth after having 
been stored for six months. 
The next recipe is that of Mr. Eudler, who (says the Reoue de Chimie 
Industrielle of March, 1899) has obtained a patent for his process in Irance:— 
Burn some vegetable fibres (turf) and some wood fibres partially, so as to 
obtain ashes perfectly free from resinous cinders. ‘The best method is electric 
combustion, so that the mixture may not contain the least particle of carbon. 
Then boil some pure water, having previously added, according to the 
quantity, from 5 to 7 per 1,000 parts of rock salt. Allow this to cool. 
Then add to the solution from 8 to 20 parts of borax. ‘This neutralises 
the salty taste. It js the same in the case of the vegetable fibre sashes. 
