Clifton College Scientific Society. 57 



equivalents of lime to one of phosphoric acid; the acid, again, is a 

 compound of phosphorus and oxygen. The process by which the 

 phosphorus is separated is rather complicated ; but the essential 

 operations are the removal of the lime by means of sulphuric 

 acid (oil of vitriol), and next of the oxygen by distillation with 

 charcoal. 



Phosphorus is of great value to the chemist, because it assists him 

 iu several important experiments — as, for instance, in separating 

 the nitrogen from the oxygen of the atmosphere, by which means 

 he is enabled to tell us the constituents of the air we breathe. 



But a much more extensive application of it is in the part it 

 plays in the manufacture of lucifer matches. Here we may observe 

 that the word phosphorus is derived from two Greek words, and 

 lucifer from two Latin words of precisely the same signification — 

 viz., light-producer. The composition in which the match is 

 dipped consists of a mixture of phosphorus, sulphur, and nitrate 

 or chlorate of potash; so that substituting charcoal for phosphorus 

 we have the ingredients of gunpowder. There are two kinds of 

 lucifers now manufactured : in one the matches are dipped in the 

 composition as above stated, and will explode with rubbing on 

 any dry, rough surface ; in the other case the phosphorus is put 

 on a separate surface, such as a piece of paper pasted on the box, 

 and then the matches will only ignite when rubbed on this surface; 

 in this case the phosphorus is in what is called an allotropic state, 

 that is, it has undergone certain changes by being kept at a great 

 heat for a long time ; among other modifications it assumes a 

 reddish colour, and is no longer spontaneously inflammable. 



The most extensive, however, if not the most important use of 

 bone-earth, is owing to the power it has been found to possess 

 of fertilising the lands to which it is applied as manure. Its 

 ordinary name in this case is superphosphate. Thousands of tons 

 of this maniu:e are produced annually in England. To change 

 the bone-earth into superphosphate, the bones are crushed and 

 mixed with a certain proportion of sulphuric acid, the efiect of 

 which is to withdraw a part of the lime ; the remainder is super- 

 phosphate. Let us now try to understand the reason of this 

 particular manure being so valuable to us. We have already seen 

 that the bones of animals contain a large amount of phosphorus, 

 but there are other tissues of the body in which the same sub- 

 stance is found — the brain and the nervous system, the milk and 

 the blood. 



Whence does the system procure this phosphorus ? Evidently 

 from the same source as that from which it draws its other con- 

 stituents — the food. We use the bodies of animals for food, and 

 their bodies in turn are built up from their food, and thus we reach 



