. 
280 On the Syflem of Forces, 
cients, for example, not being ‘acquainted: with: thelsweight. 
of the atmofphere, could not explain why water did not rife 
in a pump but toa certain height. They faid it was the 
effect of ‘an occult caufe; that is to fay, of a caufe with 
which they were unacquainted, which was concealed from 
them, ‘occulta. Many 
In the like manner we ought only to underftand by the’ 
word force the caufe of a general fa&t, whether this caufe be 
known or not. This is the acceptation in which the word 
was underftood by Newton. He obferved that all’ bodies 
had a tendency towards each other, and he called the caufe 
of this general phenomenon attractive force, or attraGtion. 
He obferved alfo, that in certain circumftances they repelled 
each other; and he called the caufe of this fecond general 
phenomenon repulfive force, or repulfion. This mode of 
expreifion:may: be applied to all the grand phenomena of na- 
ture, andiwe may ufe the word force in the following differ- 
ent fenfes : Luminous force, the caufe of the phenomena of 
light ; the caloric force, the caufe of the phenomena of heat; 
the ¢eéiric force, the caufe of the phenomena of ele&tricity ; 
_ the magnetic force, the caufe of the phenomena of magnet- 
ifm ; the galvanic force, the caufe of the phenomena of gal- 
yanifm; the |/oxorous force, the caufe of the phenomena of 
found ; the capillary force, the caufe of the. phenomsena’of 
capillary attraction; the force of affinities, the caufe of the 
phenomena, of affinity ; the difslvmg ‘force, the icaufe of 
the phenomena of folution ; the confolidating. (folidifiante) 
force, the caufe of the phenomena of folidity 5 the ery//allize 
ing force, the caufe of the phenomena of cryftallization 5, the 
. vital force; the caufe of the life of animals and vegetables’s. 
thesgenerative force, the caufe of the generation of animals 
and veeetables ;. the xutritive force; the caufe of nutrition 3). 
theyu/cular force, the caufe of mufcular motiom; ithe fim- 
pathetic force, the caufe of fympathetic movements ; the con 
coding foreethe caufe which affimilates morbific humours;! 
The number of thefe forces might be greatly extended if we 
employ. 
