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mitted the emission of the phosphoric light. The volatile alkali, 

 also in such experiments, might become a useful agent ; since, in 

 the distillation of the salt, formed by the union of this alkali, with 

 phosphoric 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 corruscating 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 heathy 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 in- 

 genious 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 dis- 

 tance, 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 inform- 

 ed 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 perform- 

 ing that good office ; they presently found their gloves, bridles, and 



