that particular trifle may later prove very useful. There would seem to be no simpler invention than the needle, yet the clothing of millions of people, and the livelihoods of millions of seamstresses, depend on the needle’s existence. Even today’s beautiful sewing machine would not exist, had the needle not long ago been invented.
b) The law of dependence teaches us that what cannot be done today, might be done later. People give much thought to the construction of a flying machine that could carry many persons and parcels. The inventing of such a machine will depend, among other things, on inventing a material that is, say, as light as paper and as sturdy and fire-resistant as, for example, steel.
Let us turn, finally, to corollaries to the law of combination.
a) Anyone who wants to be a successful inventor, needs to know a great many things – in the most diverse fields. For if a new invention is a combination of earlier inventions, then the inventor’s mind is the ground on which, for the first time, various seemingly unrelated things combine. Example: The steam engine combines the kettle for cooking Rumford’s Soup, the pump, and the spinning wheel – if the first inventor had not been familiar with these objects, if he had not combined them in his mind, would we have had steam engines?
The balloon combines lighting gas, a silk-taffeta bag, a parasol, a net, and a basket – and could the balloon exist if the minds of its inventors had not held information about these objects? What is the connection among zinc, copper, sulfuric acid, a magnet, a clockwork mechanism, and an urgent message? All these had to come together in the mind of the inventor of the telegraph…
