83 
the emission of the phosphoric light. The volatile alkali, also in 
such experiments, might become a useful agent ; since, in the dis- 
tillation of the salt, formed by the union of this alkali with phos- 
phoric acid, a gas comes over, which does not instantaneously 
inflame, but displays a phosphoric light, when it comes in contact 
with oxygen gas. 
The other phenomenon, which is yielded by the mould formed of 
the mineralized remains of vegetables, is a coruscating light, pro- 
duced by its percussion under certain circumstances. This pheno- 
menon has been seen by Dr. Plott, and others. Dr. Plott’s account 
of it is as follows ; — 
“ Under the uppermost turf, in their moorish boggy grounds, 
they also dig peats, which, because they order much after the same 
manner as has already been described in Oxfordshire, I pass them 
over, and proceed to another black, moist, and rotten sort of earth, 
that lies just under the turf in healthy soils, such as Archer Moore, 
near Berresford, and upon a hill called the Gun, above Rudyerd 
Hall, where, as I was seriously told by the worshipful and most 
ingenious Charles Cotton, Esq. Thomas Rudyerd, of Rudyerd, Esq. 
and Mr. Gent, of Asbourn, if one ride in a dark night in so wet a 
season, that a horse breaks through the turf, and throws up this 
black, moist, spongy sort of earth, he seems to fling up so much fire, 
which lies shining upon the ground like so many embers ; by the 
light whereof one horse may trace another, though at some distance, 
and it be never so dark ; it continuing light upon the ground, and 
being gradually dying away, for near a quarter of an hour. To 
which let me add another agreeable relation, whereof I was informed 
by that worthy loyal gentleman Capt. Thomas Lane, of Bentley, 
who, endeavouring to help a friend and kinsman (one Mr. Jones}, 
who casually fell in a ditch, in Bescott grounds, in the night time, 
and having stirred the mud and dirt pretty much in performing that 
good office ; they presently found their gloves, bridles, and horses. 
