CHEMISTRY. 199 



acidulated water or sea-water may be even called an established 

 fact. It is probable that a coating of the metal or paint, in so far 

 as it is impervious to water, may prevent, or at least lessen this 

 injurious action, but this has not as yet been estal)lished by direct 

 experiment. There are many engineering structures rely in «• for 

 their safety upon the strength of cast iron in contact with sea- 

 water, and the chances of injury from this action should never be 

 lost sight of during the periodical inspection of such works. — 

 Engineering. 



DISSOLVING BONES. 



The importance of phosphates, such as common bones, as fer- 

 tilizers, especially in grain culture, can hardly be over-estimated. 

 There exist, however, some obstacles which yet prevent waste 

 bones, nearly always cheap and within reach, from being gener- 

 ally used. The great distances in the far West, and other incon- 

 veniences, render their purchase in powder form expensive, and 

 for grinding them at home, or dissolving in acid, there is still 

 less chance. 



Professor Ilienhof, in Russia, has, however, lately discovered 

 a method for dissolving them, which must prove highly econom- 

 ical and suitable in unsettled countries, where, owing to the great 

 abundance of forests, wood ashes are cheaply secured — indeed, 

 are almost always at hand. This new process of treating bones 

 consists of mixing them with wood ashes and slaked caustic lime, 

 and keeping the mixture constantly moist. As in the preparation 

 of lye for manufacturing soap, the alkaline carbonates in the 

 ashes, such as carl)onate of potassa, are by the action of caustic 

 lime converted into free caustic potassa, attacking and quickly 

 dissolving the bones. 



The following practical example will illustrate the necessary 

 proceeding : Suppose the wood ashes to contain about 10 per 

 cent, carbonate of potassa, and that 4,000 pounds of bones are to 

 be worked up ; then we take 4,000 pounds of ashes, 600 pounds 

 of caustic lime, and 400 to 500 pounds of water. A ditch, some 

 2 feet deep, of such width and length as to hold 6,000 pounds of 

 the mixture, is dug, and near it a second ditch, being some 25 

 per cent, larger, and both lined with boards. The lime is then 

 slaked, and, when crumbled to a powder, mingled with the wood 

 ashes, 2,000 pounds of bones piled up in layers and covered 

 up with the mass in the smaller ditch, 3,600^ pounds of water 

 added, and the whole left to itself. From time to time small quan- 

 tities of water are added, to keep the mass moist. As soon as it 

 is found that the bones are so far decomposed that when pressed 

 between the fingers they are soft and crumble, the second portion 

 — that is, the other 2,000 pounds of bones — is brought into the 

 larger ditch, and covered in layers with the first mass, and left 

 to decompose. 



After the whole mass has undergone decomposition it is suffered 

 to dry, by removing it; and, lastly, to facilitate its reduction to 

 powder, mixed with 4,000 pounds of dry turf, or some other dry 



