Material. Copper sulphate, carbonate of soda, ammonia. Apparatus. Quart glass jar, stirring-rod, granite kettle. To make this fungicide it is necessary first to make the copper carbonate. The common formula for copper carbonate is

Laboratory formula. Weigh out two ounces of copper sulphate and dissolve in one pint of water, and in a separate vessel dissolve two ounces of carbonate of soda in one pint of water. When cool, mix the two solutions slowly, stirring well. Allow the solution to stand twelve hours to settle, after which pour off the liquid. Add one quart of water and stir a second time, again allowing the solution to stand for twelve hours. Repeat this operation several times and then filter off the residue. The blue powder thus obtained is copper carbonate. Describe fully the operation and explain each step. What is the difference between the finished product and the copper sulphate? Write out the chemical formula and give the resulting product.

The common formula for ammoniacal solution of copper carbonate is

Laboratory formula. Weigh out one fourth of an ounce of the copper carbonate just prepared and dissolve this in one eighth of a pint of ammonia. When thoroughly dissolved, add enough water to make two gallons. What is the function of the ammonia? Where is this fungicide used? How does it differ in this respect from Bordeaux mixture? Give the chemical formula of copper carbonate when mixed with the ammonia.