M. Donovan on the Preparation of Phosphorus. 205 



With regard to the quantity of earthy salts contained in harts- 

 horn, few analyses have been made. Dr. Pearson calcined his 

 hartshorn-shavings to a brown colour, and obtained 54| per cent. 

 Neumann, who only tried the tops of the horns, recoveredGOpounds 

 of black caput mortuum from 100 pounds. Many trials gave 

 me an average of 62 per cent, when the shavings were burnt to 

 whiteness. These white ashes consist almost entirely of phos- 

 phate of lime; and it appears that hartshorn by calcination 

 returns at least twice as much phosphate of lime as fresh bones. 

 The horns of a fallow-deer will weigh about \^ pound. 



These different fornas of bones and horns present us with 

 phosphate of lime ip^tates which possess different advantages : 

 some^old,_out4h6 inducement of cheapness ; some of facility in 

 employing them : all of them answer the purpose. Ground 

 bones may be procured in Dublin at so low a price as 35. per 

 bushel, weighing about 42 pounds. Bone-black, the caput mor- 

 tuum remaining after the distillation of carbonate of ammonia 

 from bones, may be had in quantity at 85. per cwt. This black, 

 by exposure to a red heat in the open air, becomes white bone- 

 ashes; but the process is not necessary. Hartshorn-shavings 

 are expensive, being so high, even in quantity, as Sd. per pound ; 

 but as the ratio of phosphate of lime contained in them is nearly 

 double, we may estimate them at 4|^^. ; and if their cleanliness 

 and facility of employment be taken into account, they become 

 still more eligible. But what renders their claims to preference 

 paramount, is that even after having been kept a very long time, 

 they contain an ingredient in perfectly good condition, which, 

 when dissolved in w^ater and properly seasoned, constitutes a 

 light, highly nutritious, and most agreeable jelly, which has 

 found its way to the kitchen, the nursery, and the sick room. A 

 legally-authorized process for preparing it is given in many of 

 the Pharmacopoeias of Europe. Bone also possesses an analogous 

 substance, which, although it cannot be extracted with the same 

 facility, and after a lapse of time is not in good condition, has 

 been recommended in its recent state as an article of food. Every- 

 one is aware of the employment of the Digester for the purpose 

 of its extraction. 



In order to remove the animal matter from the earthy portion 

 of bones, the process of calcination is resorted to ; but it is un- 

 ceconomical, and very troublesome. Instead of this, it will be 

 better and much easier to withdraw the earthy portion from the 

 animal matter, and thus preserve both for use. The separation 

 is easily effected by digesting the bones either in muriatic or 

 very dilute nitric acid : the earthy salts will thus be dissolved 

 away, and the cartilage, retaining the shape of the bone, will 

 remain unaltered. It will presently be shown that diluted com- 

 mercial nitrous acid is better adapted for the purpose. 



