The myths invented by the Greeks in their prehistoric period were the products of not only imagination but construction. Each myth was a perfectly connected story, complete in all necessary detail, admirably put together, and told in charming language. The story of Jason's Argonautic Expedition in search of the Golden Fleece cannot be surpassed in any of the elements that make a story good; Penelope is still the model of conjugal devotion, and Achilles the ideal warrior; Poseidon, or his Roman successor, Neptune, still rules the waves; Aphrodite, or Venus, calls up more vividly before our minds than any other name the vision of feminine beauty even to this day. Hercules exemplifies muscular strength, and Apollo still typifies that which is most beautiful in manliness. The influence of the Grecian myths, "pure inventions" as they were, in the sense that they were fictitious and not true, has been explained and demonstrated at great length and with abundant enthusiasm by poets and scholars for many centuries. They have been generally regarded as inventions, but nevertheless as quite different from such inventions as the steam-engine or the printing press. The present author wishes to point out that the mental processes by which both myths and engines were created were alike, and that the inventions differed mainly in the uses to which they were put. Even the uses to which they were put were similar in the end; for the use of the myths and of the steam engine was to improve the conditions of man's existence. There is only one way in which to do this, and that is by improving the impressions made on his mind. The myths did this by making beautiful pictures for his mind to gaze at, and by using them to induce him to follow a certain (good) line of conduct, rather than the contrary. The steam engine did it by making the conditions of living more comfortable, by rendering transportation more safe and rapid, and by rendering possible the procuring of many of the pleasant things of life from distant places. The invention of a myth may be said to be the invention of an immaterial thing; the invention of a steam engine to be of a material thing. These two lines of effort, invention has followed since long before the dawn of history. Of the two, the invention of myths and stories probably succeeded the other.