Organic matter 88.52 Insoluble siliceous matters 1.48 Oxide of iron 0.54 Lime 1.72 Magnesia 1.55 Phosphoric acid 4.27 Sulphuric acid 0.24 Potash 1.19 Soda 0.31 Chloride of sodium 0.18 ------ 100.00 In a sample analyzed by myself there were found-- Organic matter 86.75 Phosphates 8.19 Alkaline salts, containing 1.18 of phosphoric } 2.53 acid } Insoluble matters 2.53 ------ 100.00 Nitrogen 4.59 Equal to ammonia 5.57 It is to be observed that the urine and dung of animals differ conspicuously in the composition of their ash, the former being characterized by the abundance of alkaline salts, while the latter contains these substances in small proportion, but is rich in earthy matters, and especially in phosphoric acid. Salts of potash, for example, form nine-tenths of the inorganic part of the urine of the ox, while less than three per cent of that alkali is found in its dung. Phosphoric acid, on the other hand, is not met with in the urine, but forms about ten per cent of the dung. Silica is the most abundant constituent of the dung, but a large proportion of that found on analysis has been swallowed in the shape of grains of sand and particles of soil mechanically mixed with the food, although part is also derived from the straw and grains, which contain that substance in great abundance. The difference in the quantity of nitrogen they contain is also very marked, and is distinctly shown by the following analyses by Boussingault, which give the quantity of carbon, hydrogen, nitrogen, oxygen, and ash in the dung and urine of the horse and the cow in their natural state, and after drying at 212 deg..