Only in connection with chance, then, can Reason find in cards a task worthy of her powers, and, indeed, a small prize is a stimulus sometimes needed to keep up our interest. This may be a suitable place to mention that it was formerly the custom to play for money or some stake with all games of chance and even with chess. I close this review of contests which are purely intellectual with two brief remarks, the first of which concerns the invention of board games. It is difficult to find a perfectly satisfactory answer to the question of their origin. However, their complication points to adults rather than children as their probable inventors, and to me the following consideration seems important: The primitive races, who find it difficult to convey their thoughts in speech, naturally take to marking on the sand, and hence the figures might arise.[401] If the leader of one of the more intelligent peoples wished to instruct them concerning some past or future combat, it would be a simple method of illustrating his meaning to draw an outline on the ground and represent the position of the hostile forces by small stones or similar objects whose movements would symbolize the manœuvres of the forces or the advances of knights for single combat. This would, no doubt, be exceedingly interesting to those conducting it, and also to the spectators, and might easily be repeated for the sake of the amusement afforded until some inventive genius turned it into a veritable play with board and men. To show that there is nothing improbable in this supposition we may point to the fact that such play is actually carried on by our own officers (Italian, _manovra sulla carta_).