CHEMISTRY AND FARMING. 305 



struct it himself. The excavation may first be made, then the 

 mortar prepared by mingling with the cement enough water to 

 form a tolerably liquid paste, then working up with it an equal 

 quantity of coarse sand. It may be applied to the interior of 

 the cavity by the use of the hoe and the shovel. In the centre 

 of the plank covering, a box, at least one foot square, should be 

 inserted, to which a tight cover may be fitted, to serve as an 

 opening into the cistern. In cold, frosty weather in winter the 

 liquid of the cattle stalls will be congealed. In this state it will 

 not pass through conductors, but may be taken up with the 

 shovel and thrown into the cistern through the opening. In 

 arranging the cistern the farmer must not omit to place it so 

 that all the drainings of the barnyard will flow into it. This 

 can be done on the premises of most farmers. It is of the 

 utmost importance to his prosperity that not one drop of the 

 rich dark liquid which pervades his barnyard, especially in the 

 spring, should be lost. Even if it does not escape by some out- 

 let, by standing exposed to the air, the ammonia which is formed 

 is lost by escaping into the same, and thus he is robbed of his 

 treasure. 



The yard should always have a slight depression in the 

 centre, so that all the drainings will gravitate towards that 

 point ; then, by a proper pathway, they may be conducted into 

 tlie cistern. 



The farmer should always have at hand a vessel of oil of 

 vitriol, or sulphuric acid. He will need it, not only for his 

 drainings, but for compost and for dissolving bones. It is pur- 

 chased in strong, well-protected glass carboys, holding several 

 gallons. Its cost is trifling, not more than two or three cents 

 per pound. It should be kept in an outhouse, and handled 

 with care, and when wanted for use, diluted with at least an 

 equal measure of water in a strong wooden bucket. 



It is difficult to state exactly how much or how often it should 

 be added to the drainings in the cistern. We may form an 

 approximate estimate, however, which will perhaps afford suf- 

 ficiently accurate guidance in this particular. 



A half-pint of acid is fully sufficient for one hundred pounds 

 of the urine of a cow. Suppose then each one to produce this 

 amount weekly, and you have in your stalls two ve in number, 

 you will be required to add, each week, three quarts of acid. 



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