VOL. XXXVI.] PHILOSOPHICAL TRANSACTIONS. 337 



make their parts touch each other close enough, so as to come within their 

 sphere of activity ? 



Query 1. — Having often found the touching surfaces of such leaden balls, as 

 near as could be measured, much alike; yet the force of cohesion very different: 

 nay, the touching surfaces have been very small, yet sometimes 114 to 1261b. 

 weight has not been sufficient to separate them ; when at other times a far less 

 weight, though the measure of touching surfaces far exceeded those mentioned, 

 was more than sufficient to cause their separation. Does it not prove that the 

 cohesion is strongest according to the closeness of the contact, but not as the 

 touching surfaces } for which reason the cohesion is always strongest, when a 

 little twist is given in joining them ; since by this means the particles must come 

 closer together, than by squeezing the balls barely on each other, thougli it 

 was done with a far greater force than could be applied with the bare hands. 

 And since the force, twist, and touching surfaces can never be alike and 

 mensurable when joined by hand, it will be very difficult, if not impossible, to 

 ascertain the forces of this cohesion, which is incredible, and far exceeds mag- 

 netical attractions. 



Query 3. — Does not this experiment fairly account for the cohesion of the 

 parts of matter; and that this firm cohesion cannot be derived from any glue 

 or cement, any imaginary hooks and funiculus, nor de gravitate etheris : but 

 that the particles of all solid and fluid bodies attract each other by a certain 

 force, which acts most intensely the nearer they touch each other. 



Our Dahlkarlians have, time out of mind, practised an experiment, when 

 they have had occasion to remove any unwieldy stones of the hardest rocks, 

 and so large as not to be moved entire by any strength they could apply. They 

 practise the following means, not only to cleave and split them into as many 

 parts and pieces as they please, but they obtain stones with one or more smooth 

 sides, fit for use in buildings. Their method is thus : 



They take tallow, grease, train oil, or any other fat substances, with which 

 they draw lines on such large stones, according as they would have them split, 

 and think proper ; then they lay either charcoal or wood at top, and round the 

 sides of the stone, so that it is all over covered, and then kindle the fuel ; which 

 when burned out, they find the stone divided according to the lines they have 

 drawn on it, with some of the beforementioned fat substances, which seldom 

 or never fails. 



May we not account for this odd phenomenon thus ? That as the action of 

 heat and fire expands the parts of all hard and solid bodies, and metals them- 

 selves; so when the action of the fire about the stone has made the particles of 

 the same recede farther from each other, than when in their natural state, the 



VOL. vix. X X 



