The countenance of the average Negrito is not dull and passive, as might reasonably be expected, but is fairly bright and keen, more so than the average Malayan countenance. The Negrito also has a look of good nature--a look usually lacking in the Malayan. His knowledge of things other than those pertaining to his environment is, of course, extremely limited, but he is possessed of an intellect that is capable of growth under proper conditions. He always manifests the most lively interest in things which he does not understand, and he tries to assign causes for them. Natural phenomena he is unable to explain. When the sun sets it goes down behind a precipice so far off that he could not walk to it, but he does not know how it gets back to the east. Rain comes from the clouds, but he does not know how it got there except that thunder and lightning bring it. These things are incomprehensible to him and he has apparently invented no stories concerning them. While thunder and lightning are good because they bring rain, yet if they are exceedingly violent he becomes afraid and tries to stop them by burning deer's bones, which, he says, are always efficacious. The mathematical knowledge of the Negritos is naturally small. They count on their fingers and toes, beginning always with the thumb and great toe. If the things they are counting are more than twenty they go through the process again, but never repeat the fingers without first counting the toes. To add they use rice or small stones. They have no weights or measures except those of the civilized natives, but usually compare things to be measured with some known object. Distance is estimated by the time taken to walk it, but they have no conception of hours. It may take from sunrise until the sun is directly overhead to go from a certain rancheria to another, but if asked the number of hours the Negrito is as likely to say three or eight as six. They have no division of time by weeks or months, but have periods corresponding to the phase of the moon, to which they give names. The new moon is called "bay'-un bu'-an," the full moon "da-a'-na bu'-an," and the waning moon "may-a'-mo-a bu'-an." They determine years by the planting or harvesting season. Yet no record of years is kept, and memory seldom goes back beyond the last season. Hence the Negritos have no idea of age. They know that they are old enough to have children or grandchildren, and that is as far as their knowledge of age goes. To count days ahead they tie knots in a string of bejuco and each day cut off one knot.