294 Dr. Pearson’s Experiments for 
charged, was then bent so that the open end might be kept 
conveniently plunged in quicksilver during the experiment. 
The coated part of the tube, containing the alkali, excepting two 
or three inches next to the phosphorus, was gradually heated 
over a portable furnace till it was red hot, and rather flexible, 
in which state the part containing the phosphorus was gra- 
dually drawn over the fire, and kept red hot twenty minutes. 
At the beginning of the experiment, quicksilver rose several 
inches within the tube, and when the coated part grew hot, 
phosphorus was sublimed into the upper and cool part of it : 
about twenty drops of water were condensed over the quicksil- 
ver ; and two ounce measures of phlogisticated air, with a little 
respirable air, which had the smell of phosphorus, came over. 
The tube, when cold, being broken, the lower part was found 
to contain a loosely-cohering solid, as black as charcoal, which 
weighed 428 grains, and above this, a grey and white sub- 
stance, partly fused, and partly in a powdery form, which, with 
adhering glass, weighed 358 grains. Neither in this, nor in 
other similar experiments, w as I able to collect the whole con- 
tents of the tube, without glass which had been melted, that 
adhered to the alkali, on w'hich account I could not determine 
accurately the total weight, independently of glass ; but I was 
sure, from a number of trials, that it was a little less than the 
original weight of the alkali. The phosphorus, sublimed into 
the upper part of the tube, was moist from the adhering phos- 
phoric acid : it was inflamed by slight friction, viz. merely on 
breaking the tube. 
The 428 grains of black alkaline matter thus obtained, af- 
forded, by solution in boiling hot concentrated acetous acid, a 
little more than 25 ounce measures of carbonic acid, under the 
mean pressure of the atmosphere, and of the temperature of 
