144 A VISIT TO A BONE BOILING FACTORY. 



which the beak of the retort clips. It is afterwards purified by filtra- 

 tion through leather in hot water, and is finally melted, likewise under 

 water, in conical moulds, by which it assumes the usual appearance of 

 stick phosphorus. 



Many are the things thrown away as useless which, when circum- 

 stances allow of their being collected in considerable quantities, are 

 found to be applicable to a variety of useful purposes ; and in none is 

 this observation more remarkably exemplified than in the subject of the 

 present illustration. Thus, on investigation, we find that bone contains 

 a considerable quantity of valuable nutriment, which may be extracted 

 with greater or less ease in proportion as its cohesion is more or less 

 overcome — that in its entire state it forms excellent handles for small 

 brushes, and is also applicable to a variety of other similar uses — that 

 the worker in steel employs it for case-hardening small and delicate 

 articles — that, in proportion to its weight, it is the most valuable and 

 active of all manures, and contributes in no inconsiderable degree to 

 improve and increase the agricultural produce of all the districts where 

 it is employed — that, in the absence of other combustibles, it may be 

 and is largely used as fuel in the plains of Tartary and South America 

 — that, by its decomposition in close vessels, it produces hartshorn, 

 ammonia, and animal charcoal — and that, when burnt to ashes, it 

 becomes useful to the assayer, furnishes a valuable polishing powder, 

 and is the material from which phosphorus, that curious and interesting 

 substance, the most combustible of all solids, is produced. 



Our guide then showed us over the remainder of this large establish- 

 ment, viz., the extensive departments for producing sugar and soap ; the 

 latter being made in large quantities, the description of these would 

 however occupy too much space, and are already pretty well known. 



