272 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



Mr. Solon Eobinson. — Break the bones as fine as possible with a ham- 

 mer, and put them in five gallons of water, with one gallon of sulphuric 

 acid. Handle the acid with care. A good thing to use it in is an old ket- 

 tle, painted thickly on the inside with some earthy paint. A Scotch farmer 

 gives his rule as follows: Add 340 pounds of sulphuric acid to 25 bushels 

 of fine bones, and wet with 18 gallons of boiling water. Let it stand two 

 days, and then mix the bones with two cart loads of fine mold, where they 

 heat and become fine powder in the course of six or eight weeks. Bones 

 will become fine if broken and mixed with ashes or fine mold, but they 

 should be kept moist. I hope Prof. Mapes will give us his experience in 

 this matter. 



Prof. Mapes. — You will find it a very tedious business to break bonea 

 with a hammer, unless they are previously boiled in alkali to extract the 

 oil and weaken the gelatine. Fresh bones cannot be ground fine in any 

 mill, and although phosphate made from such bones would be more valua- 

 ble, it would also be expensive, as the oil and gelatine protect them from 

 the action of the acid, and require more to dissolve them, so that it is 

 more economical to burn the bones before attempting to make them fine. 

 If fresh bones are mixed with ashes, unbroken, and the heap covered with 

 loam, and moistened, the bones will be so afiected as to be easily made 

 somewhat fine, and may be applied to land in that state. Burnt bones are 

 not valuable unless treated with acid. When the bones are burnt and 

 broken, put them in a hogshead lined with brick laid in clay, mortar at the 

 bottom, and wet them with sulphuric acid, mixed one to ten with water, 

 and occasionally draw off the water and add it to the compost heap, and 

 apply more acid and water to wet the bones, and they will take up as 

 much weight of acid as there is of bones, and make a valuable superphos- 

 phate. It will cost about $46 a ton to make, and will be cheap manure at 

 that, where bones can be easily obtained. One ton of fresh bones, burned 

 and treated with acid, will make half a ton of superphosphate; and 640 

 pounds will produce as good results, upon well prepared land, as eighty 

 loads of manure. If land is underdrained, subsoiled and deeply plowed, it 

 does not require nitrogenous manure. That will be absorbed from the 

 atmosphere by the fresh, finely pulverized, deeply tilled soil; and the use 

 of phosphate enables such soil to accumulate more nitrogen, which is uti- 

 lized by the crops. All soils are benefited by adding potash. Of course, 

 those best prepared are most benefited. It gives the silicate that is needed 

 to give strength to all straw, and is a cheap manure at the usual commer- 

 cial value of the cheapest kind of potash. It may be used in any quantity 

 that a farmer can afi'ord, and will pay a profit upon the cost. 



Mr. John G. Bergen. — I always burn my bones upon a brush heap, enough 

 to make them brittle, and then break moderately fine, and apply them in 

 that way to the land. 



Prof. Mapes. — That may do if the bones are only partially burnt, but it 

 has been fully proved that perfectly calcined bones of the sugar refiner 

 will never decompose in the soil unless acted upon by acid. I tried two 

 tons upon an acre without benefit, and much larger doses proved valueless 

 in Massachusetts. Unburnt bones will decompose and give up their phos- 

 phate to plants in time, though their decay is very slow; and if purchased, 



