208 M. Donovan on ttie Preparation of Phosphorus. 



retort of ordinary size would not hold a sufficiency of it to re- 

 turn a remunerative product of phosphorus. This inconvenience 

 is not peculiar to the processes here given, but affects all others 

 equally in which a salt of lead is employed. There is however 

 an easy remedy. Let the phosphate of lead be transferred to the 

 kind of crucible called a skittle-pot, and let the crucible covered 

 be heated red-hot in a common coal fire : it will during the 

 heating shrink at least to one-half its former bulk; but the 

 weight will be scarcely diminished. It will be still a loosely 

 aggregated pulvei-ulent mass ; if the heat be increased, it will 

 shrink more and melt, but it then becomes rather difficult to 

 powder. 



The last step in the process is the distillation of the phosphate 

 of lead with charcoal. The phosphate and charcoal, both in fine 

 powder, and well mixed, are to be introduced into an earthen- 

 ware retoi-t, the pores of which have been closed with a glaze 

 consisting of borax and lime as directed by Higgins. 



On account of all the foregoing facts, I conclude with recom- 

 mending the following as the easiest and cheapest processes for 

 obtaining phosphorus : — 



Take of dense bones, crushed or broken into small pieces, as 

 many pounds as may be deemed sufficient, say ten avoirdupois 

 pounds. Digest them in a mixture of 6 pounds of commercial 

 nitrous acid and five gallons of water for a few days. When the 

 bones feel perfectly soft and flexible, strain oif the liquor, and 

 add to it 8 pounds of sugar of lead dissolved in a sufficiency of 

 water. An abundant precipitate will appear ; wash and dry it by 

 heat in the manner already directed. Its bulk will be reduced to 

 one-half if it be heated red-hot in a crucible. Mix it well with 

 one-sixth of its weight of fine charcoal powder or lampblack, 

 and distil out of large earthen retorts properly prepared. 



The phosphate of lead resulting from the above process would, 

 according to my trial, amount to 91^ ounces avoird. Giobert 

 states that 100 parts of phosphate of lead precipitated from urine 

 by acetate of lead affbrded from 14 to 18 parts of phosphorus. 

 If this be a correct estimate, the 91^ ounces should return from 

 12 ounces to 1 pound of phosphorus. A large quantity of car- 

 tilage is also obtained, which is well calculated for making size, 

 glue, and for many other purposes. 



The following is a shorter, neater, and less troublesome, 

 although a little more expensive process for preparing phos- 

 phorus, which may be employed when the quantity required is 

 not very large. Take of unburnt shavings of hartshorn 1 avoir- 

 dupois pound ; digest it for four hours in a mixture of 17 ounces 

 weight of commercial nitrous acid and one gallon of water. 

 Strain the liquor, and add to it 1 j pound of sugar of lead, pre- 



