574 



THE POPULAR SCIENCE MONTHLY. 



skillful cultivation. The industry thrives in 

 the province of Kampot, where it is pursued 

 in some twenty villages. At the village of 

 Suam Ampil there are eighty-nine planters 

 and more than a hundred plantations, con- 

 taining 48,441 stocks. The plants are propa- 

 gated from cuttings, which are made about 

 eighteen inches long and are taken from 

 stocks two or three years old ; they are sup- 

 ported by stakes about ten feet high, which 

 are solidly planted in the ground ; and are 

 fertilized at the same season every year with 

 a special manure which is composed of eight 

 parts of good soil and one part of pounded 

 shrimp shells. The plants are liable to at- 

 tack by a minute parasite that destroys their 

 f ruitfulness, to obviate which they are treated 

 with a decoction of tobacco. The first crop, 

 but an insignificant one, appears in the third 

 year from planting. A crop of about a kilo- 

 gramme per stake of two plants is gathered 

 in the fourth year, and the increase continues 

 for eight or ten years. Exceptional plants 

 in good soil may return four kilogrammes per 

 stake ; but a crop of from two to two kilo- 

 grammes and a half is considered a fair 

 average. Some plants will live fifty years, 

 but they are seldom remunerative after forty 

 years ; and, as a rule, a plant thirty-five years 

 old is considered of no further value. The 

 plants bloom in May and June, and the 

 gathering of the crop begins in February. 

 The bunches which have turned red are 

 picked, and the others are left for future 

 visitations. The berries are stripped from 

 the bunches and dried in the sun till they 

 are black, when they are packed and made 

 ready for sale. White or gray pepper is pro- 

 duced by letting the berries get a little riper, 

 and cleansing them from their outside en- 

 velopes. In some districts the removal is as- 

 sisted by soaking the berries in sea-water. 

 One laborer can usually take care of about 

 one thousand stakes. 



Yaks, Wild and Domestic. — Immense 

 herds of wild yaks still pasture on the steppes 

 in the region of the Lob Nor and Thibet. In- 

 dividual species have been domesticated and 

 are as cows and oxen to the people of the 

 country. Thick and strong cloths are made 

 from their hair ; the tufts of their tails are 

 used in standards ; their meat is juicy, and 

 their milk is not inferior to that of our do- 



mestic cows ; and they are highly valued by 

 the Thibetans as draught and pack animals, 

 and even for riding, on account of their 

 hardiness, readiness, and sure-footedness. 

 Attempts have been made to domesticate 

 them in France, but the climate proved not 

 suitable to them. Comparison of the skins 

 of domestic yaks with those of wild ones 

 shows how the animal has been modified 

 under human influence and through changes 

 in its medium. The hide of the domestic 

 yak has become fine, is often silver-white, or 

 gray varied with white ; and the horns, when 

 they have not disappeared, form a simple 

 curve outward and upward ; while in the 

 wild yak the hide is uniformly black or very 

 lightly shaded with brown, and the horns, 

 which are nearly three feet long, describe an 

 incomplete S, starting outward, then grow- 

 ing forward and then upward. Judging 

 from the specimens presented to the Paris 

 Museum by the Prince of Orleans, the wild 

 yaks are much larger than the domestic ani- 

 mals, and the long hair on their flanks and 

 legs grows lower down. Like the buffalo, 

 these animals are dangerous to hunt, unless 

 they are killed at the first shot. 



Color Phenomena on Mars. — Prof. W. H. 

 Pickering writes to the Journal of Astronomy 

 and Astro-Physics concerning his observa- 

 tions of Mars at Arequipa, Peru : " The sud- 

 den changes of color exhibited by some of 

 the smaller areas upon the planet Mars are 

 sometimes almost startling. A recent view 

 was obtained shortly before sunrise, when the 

 snowy region about the south pole appeared 

 of a most brilliant green, quite equaling in 

 color the rather narrow green band situated 

 just to the north of it. Later, as the sun came 

 up, the color of the snow changed to a bright 

 yellow, the rest of the disc changing in the 

 mean time to orange. Later the seeing im- 

 proved, several of the canals became visible, 

 and the snow became as colorless as upon 

 our surrounding mountains. The two former 

 effects were probably due to bad seeing, the 

 fluctuations of our own atmosphere super- 

 poring the colors of the surrounding regions 

 upon the snow. We have laid it down as a 

 rule never to rely greatly upon our color ob- 

 servations unless the snow-caps of the planet 

 appear perfectly colorless and the canal sys- 

 tem is well defined." A curious feature of 



