XV. The axiom _Vis unita fortior_, I apprehend, applies more justly to civil and political things, than to natural ones. If we attend, we shall find that two agents, each of which is strong in proportion to four, by being joined together, will not be stronger than in proportion to eight. If two men separately can support but four half hundreds each, by joining them together, you would find them not able to support above eight. It is true, that a man who breaks arrows one by one, cannot break a bundle of arrows tied together, which is the comparison that Scilurus availed himself of (Plut. in Apophth.) to persuade his sons to continue in fraternal union; but we should not understand by this, that by binding them together, each arrow separately acquired any additional strength, for this example was only intended to shew, that he who could with ease break each arrow separately, was not sufficiently strong to break the whole bundle united together. Suppose, for instance, the bundle was to consist of twenty arrows, if there was any thing less than a twentieth part of the force exerted to break a single arrow, than it was necessary to exert to break the whole bundle, it is as certain that that single arrow would not be broke, as that the whole bundle would not. Thus this example does not prove, that there is any additional virtue or strength added to the wood of which the arrows are made, by uniting them together, but only, that twenty joined together can resist a greater force than one singly, which is a thing that is self-evident. XVI. Nothing can be plainer than this; but abstracted from the force of this reasoning, experience has shewn us, that in some agents, in contradiction to the common opinion, their union has diminished their strength. It is the general sentiment, that two threads twisted together and united in one cord, will support more weight than they will separately; and that a rope made of many fine threads, is stronger than all these threads divided. Mons. Reamur, of the Academy Royal of Sciences, demonstrated in 1711, that the fact was quite otherwise, and that the threads separate would support a greater weight than they would united. He made this experiment with two single threads, and found that each by itself would support nine pounds and a half, which put together make nineteen pounds; after this he caused them to be twisted together, and they were broke with sixteen pounds. He made another experiment with three threads, one of which supported six pounds and a half; another eight, and another eight and a half; the sum of all which put together amounted to twenty-three pounds; and after causing them to be made into a cord, they would not sustain more than seventeen.