The Cause of Solidity
Table of Contents
On what depends the resistance to breaking, other than that of void?
What is the gluey or viscous substance which cements together the parts of the solid?
If gold, silver and glass are kept for a long while in the molten state and are removed from the furnace, their parts, on cooling, immediately reunite and bind together as before.
What holds these parts together so firmly?
The 2 plates can be separated only with violent effort.
They are held together by the resistance of the void.
The same can be said of 2 large pieces of a marble or bronze column.
This same cause explains the coherence of the very smallest particles of these materials.
You have already proved that a large vacuum prevents the separation of 2 large parts of a solid is very small compared to the cohesive force which binds together the most minute parts.*
Why do you not regard the cohesive force as something very different from the preventive force?
Superphysics Note
Sagredo has already answered this question when he remarked that each soldier was being paid from coin collected by a general tax of pennies and farthings even if 1 million of gold would not suffice to pay the entire army.*
Superphysics Note
There may be other extremely minute vacua which affect the smallest particles.
- That which binds together the contiguous parts might be of the same mintage.
Fire winds its way in between the most minute particles of metal.
Even though these are solidly cemented together, fire tears them apart and separates them.
After removing the fire, these particles reunite with the same tenacity as at first.
- They keep the same quantity in the case of gold and with little loss in the case of other metals.
- This is even though these parts have been separated for a long while
My reason is that the extremely fine particles of fire penetrates the slender pores of the metal.
- These pores are too small to admit even the finest particles of air or fluids.
- The fire would fill the small intervening vacua and would set free these small particles from the attraction.
These same vacua exert on them and which prevents their separation.
Thus the particles are able to move freely so that the mass becomes fluid.
- It remains fluid as long as the particles of fire remain inside.
- But if they depart and leave the former vacua then the original attraction returns and the parts are again cemented together.
Each particular vacuum is exceedingly minute and therefore easily overcome.
Yet their number is so extraordinarily great that their combined resistance is multiplied almost without limit.
The nature and the amount of force which results from adding together an immense number of small forces [debolissimi momenti] is illustrated by the fact that a 1 million pound weight suspended by great cables is overcome and lifted when the south wind carries innumerable atoms of water.
These atoms are suspended in thin mist which moves through the air and penetrate between the fibres of the tense ropes in spite of the tremendous force of the hanging weight.
When these particles enter the narrow pores they swell the ropes, thereby shorten them, and perforce lift the heavy mass [mole].
Any resistance, so long as it is not infinite, may be overcome by a multitude of minute forces.
Thus, a vast number of ants might carry ashore a ship laden with grain.
One ant can easily carry one grain. The number of grains in the ship is not infinite, but falls below a certain limit.
If you take another number 6 times as great, and if you set to work a corresponding number of ants they will carry the grain ashore and the boat also.
This will call for many ants. But I think this is precisely the case with the vacua which bind together the least particles of a metal.
But even if this demanded an infinite number would you still think it impossible?
Not if the mass [mole] of metal were infinite; otherwise.