[Illustration: TRIBAL MARKS or WASMs of the ARABS.] _Athr_ or _ilm el athar_ is the science of footsteps; and like the free Indians of America, the Arab is keen to study and quick to judge from sand tracks of both men and animals. The genuine Arab who has made _athar_ a study can tell the track of a friend from that of a foe, and can distinguish the tribe or even the clan; he knows from the depth of the footprint whether the camel was loaded or lame; whether the man passed yesterday or a week before; from the regularity or irregularity he judges of fatigue or of pursuit. If the camel’s forefeet dig deeper than the hind he concludes the animal had a weak breast; from the offal he knows whence the camels came and the character of their pasture. Burckhardt writes of instances where camels were traced six days’ journeys after being stolen, and identified. To identify property it must be marked, therefore, the kindred science of _wasm_ has its place. A _wasm_ is a Bedouin trade-mark or ideograph to label his property, real and personal. Their origin is unknown, although Doughty says that they ofttimes resemble Himyaritic letters and may therefore come from Yemen. Each family or tribe has its own cattle-brand or token. Not only is personal property such as cattle marked with the _wasm_ but the Bedouin put their mark on rocks near favorite wells or pastures. These signs are the only certain records of former occupation of tribes. Many of the tribes have two or three different _wasms_; these belong to family groups.