Simple exercises illustrating some applicants of chemistry to agriculture by Hatch Kirk Lester 1871-

Author:Hatch, Kirk Lester, 1871- [from old catalog]
Language: eng
Format: epub, pdf
Tags: Agricultural chemistry
Publisher: Washington, Govt. print. off.
Published: 1908-03-25T05:00:00+00:00

Fig. 4.—Apparatus used in preparing hydrogen.

gen under the influence of heat) water is formed. The observation shouhl be made before the flame has had time to heat the glass, otherwise there Avill be no condensation of moisture on the glass.

Exercise 11.— To Prepare Potash.

Potash is easily prepared from wood ashes. Pour 2 or 3 quarts of water over a pan half filled with wood ashes and stir water and ashes together thoroughly. Set aside for a time and stir again. Repeat this several times, in order completely to dissolve the potash contained in the ashes. "When the ashes have finally settled, pour off the clear liquid on the top into another vessel, set it on the stove, and evaporate to dryness. The dry, white substance found on the bottom of this dish is potash. A little of it dissolved in water will make the water feel soapy. This " soapy feel " is a test for alkalis, to which group potash belongs. Repeat this exercise after Exercise 24 has been performed, and test the potash with litmus paper.

Exercise 12.—To Prepare Phosphoric Acid.

• Phosphoric acid, uncombined with other elements, is very difficult to obtain. P^or illustrative purposes, crude phosphoric acid may be easily jDrepared from bones by burning them to whiteness. Burned bone is practically a combination of phosphoric acid and lime. The lime may be removed by placing the burned bone, finely pulverized, in a bottle, covering it with water, and adding a small quantity of sulphuric acid. The lime Avill combine with the sulphuric acid and settle to the bottom and the clear liquid above it will contain the phosphoric acid. This is a very simple way to prepare it, and the liquid is sufficiently pure for illustrative purposes.

Exercise 13.—To Test Stone for Lime.

Break off a piece of stone as large as a hickory nut and pulverize it by pounding it with a hammer. Make a very fine powder, put the powder in a glass, cover it with water, and add a small quantity of sulphuric acid.° If the stone is a limestone, little bubbles of carbonic-acid gas will come off. Test it with limewater. If no gas comes off, the stone contains little or no lime.

Exercise ]4.—To Prepare Lime.

When a stone is known to contain lime it may be converted into the kind of lime used by builders by burning it in a stove for a day or two. When thoroughly burned take it out and make some limewater from

" Observe the precautions noted on page 8 regarding the use of acids.

[Bull. 195]

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