102 
“ Indeed, it must be allowed, that sometimes whole mountains are com¬ 
posed nearly wholly of vitriolated or aluminous marchasites. 
u Also that the rains sink through the spongy substance of the earth, and 
finding a proper channel, constitute springs, containing within their pores the 
nitro-aerial particles * as essential to the production of fire, which the air- 
pump demonstrates.” 
“ For if rain or other water be put into a glass, and the air extracted from 
this by suction, immediately are seen numerous bubbles of air rushing from 
the body of the water.” 
“ We may now remark, that if these a a lino - 4 ulp hureoud mountains be 
humected with water , an effervescence will take place, and heat be induced.” 
“ For if marchasites, or any salino-sulphureous glebe, mixed with either 
vitriol, or any similar salt, be exposed abroad to an humid atmosphere, or 
the rains of heaven, these in a short time will in a remarkable way ferment. 
Thus also, if any a alino-sulphureous mineral , recently dug up, be moistened 
with rain, this in a short space of time will ferment and give out heat." 
u In confirmation of this doctrine,” continues Mayow, “ the high hills 
by which the wells of Bath are surrounded, abound with mar charted, and 
these waters shew an impregnation of the nature of an acid , for if any alkali 
* The nitro-aerial particles, or oxygen, may arise also in part from the decomposition of the mi¬ 
neral acids . If we mix two parts of spirits of wine with one of fresh fuming spirits of nitre '(the 
oxygenated nitric acid) the mixture will remain cold for near ten minutes, and it will after that time 
begin to acquire some degree of heat, till at length it will boil with great violence for a considerable 
length of time. 
In like manner, by mixing togethei equal bulks of strong spirit of vitriol (the sulphuric acid) 
with water, we can raise from these bodies, previously cold, a degree of heat nearly equal to what 
boiling water exhibits. 
If the fuming acid of nitre (the nitric acid) be mixed with oil of turpentine, let it be in the depth 
of winter, and when these two fluids are severally colder than ice, yet you will see them, to the utter 
astonishment of those not much versed in chemical phenomena, instantaneously catch fire, and kindle 
a powerful flame. A pint of each being employed will raise a column of fire'and smoke more than 
twenty feet in height. 
In the Philosophical Transactions for 1699, we have a table expressing at one view, the effect 
which the nitrous add has upon a variety of other oils, as well as that of turpentine, and we find 
there enumerated twelve sorts of oils, which, when mixed with the add of nitre (the nitrous acid) 
effervesced and exploded with a flame. 
In addition to the information contained in this table, we are indebted to the French chemists for 
a variety of interesting memoirs on the inflammation of oils, both by the simple nitrous acid, and by 
that acid, when mixed with the vitriolic acid. 
Musschenbroeck has related above 200 experiments, illustrating the alteration of the temperature 
arising from the mixture of different substances with water, spirits of wine, and the mineral and 
vegetable acids. 
