Modern travellers bear witness to a gradual progress of desiccation in the Tibetan uplands.
During their removal it is important that the roots be covered, if only to prevent desiccation by the air.
The occurrence of characteristic algae at different levels constituting the zones to which reference has already been made, is probably in part an expression of the fact that different species vary in the capacity to resist desiccation from exposure.
Algae of more delicate texture than either Fucaceae or Laminariaceae also occur in the region exposed by the ebb of the tide, but these secure their exemption from desiccation either by retaining water in their meshes by capillary attraction, as in the case of Pilayella, or by growing among the tangles of the larger Fucaceae, as in the case of Polysiphonia fastigiate, or by growing in dense masses on rocks, as in the case of Laurencia pinnatifida.
The desiccation of the rivers of Russia has been often attributed to the steady destruction of its forests.
From the statements of older travellers, like the Venetian Marco Polo (13th century) and the Chinese pilgrim Hsiian Tsang (7th century), as well as from other data, it is perfectly evident, not only that this country is suffering from a progressive desiccation, but that the sands have actually swallowed up cultivated areas within the historical period.
The area of the lake is shrinking owing to the progressive desiccation of the country, Saharan climate and conditions replacing those of the Sudan.
In the east, the country of Kanem, the desiccation has been most marked.
In the north-west to over 20 in the south, where desiccation is less apparent.
Many of the great historic movements of peoples were doubtless due to the gradual change of geographical or climatic conditions; and the slow desiccation of Central Asia has been plausibly suggested as the real cause of the peopling of modern Europe and of the medieval wars of the Old World, the theatres of which were critical points on the great natural lines of communication between east and west.
Steppes, their desiccation, the consequence of the above causes, is in rapid progress.'
Even within historical times and during the 19th century the desiccation of the lakes has gone on at a very rapid rate.
Since the first advent of white colonists many springs and pans and small streams have dried up, this desiccation being attributed, not so much to decreased rainfall, as to the burning off of the grass every winter, so that the water, instead of soaking in, runs off the hard, baked'ground into the larger rivers.
But many of the simpler P Y ler P forms of life may undergo desiccation to such an extent as to arrest their vital manifestations and convert them into the semblance of not-living matter, and yet remain potentially alive.
The Guanches embalmed their dead; many mummies have been found in an extreme state of desiccation, each weighing not more than 6 or 7 lb.
In the higher parts there are fine plains where Glaser found numerous Himyaritic remains, and which he considers were undoubtedly cultivated formerly, but they have long fallen out of cultivation owing to denudation and desiccation - the impoverishment of the country from these causes is increasing.
Among his other works may be named Paroles d'un revolte (1884); La Conquete du pain (1888); L' Anarchic: sa philosophie, son ideal (1896); The State, its Part in History (1898); Fields, Factories and Workshops (1899); Memoirs of a Revolutionist (1900); Mutual Aid, a Factor of Evolution (1902); Modern Science and Anarchism (Philadelphia, 1903); The Desiccation of Asia (1904); The Orography of Asia (1904); and Russian Literature (1905).
Similarly secular elevations of temperature, either accompanied by moisture or desiccation, by increasing droughts or by disturbance of the balance of nature, have been followed by great waves of extinction of the Mammalia.
After the great ice cap had thawed and a period of general desiccation set in, the Caspian began to shrink in area, and simultaneously its connexions with the Black Sea and the Sea of Aral were severed.
This desiccation is partly attributable to the unrestricted felling of wood practised for many centuries by the inhabitants.
In the case of the freshwater algae, however, belonging to the Chlorophyceae and Cyanophyceae, although they required to be immersed during the vegetative period, the reproductive cells are often capable of resisting a considerable degree of desiccation, and in this condition are dispersed through great distances by various agencies.
The occurrence of a plentiful mucilage in many freshwater forms is, however, doubtless a provision against desiccation on exposure.
During this period, wind-blown deposits, such as the loess, began to make their appearance.
The lake is undergoing a process of desiccation, and in some dry seasons (as in 1879 and 1903) the "open water" is reduced to a number of large pools.
The question of the gradual desiccation of the Volga, and its causes, has often been discussed, and in 1838 a committee which included Karl Baer among its members was appointed by the Russian academy of sciences to investigate the subject.
But it is obvious that there are other general causes at work, which are of a much more important character - causes of which the larger phenomena of the general desiccation of Eastern and Western Turkestan are contemporaneous manifestations.
The gradual elevation of the whole of northern Russia and Siberia, and the consequent draining of the marshes, is one of these deeper-seated, ampler causes; another is the desiccation of the lakes all over the northern hemisphere.
Possibly the ordinary processes of denudation and erosion, acting on those recent deposits which overlie the harder beds of the older series, may have much to say to these climatic changes, and the wanton destruction of forests may have assisted the efforts of nature; but it is difficult to understand the widespread desiccation of large areas of the Baluch highlands, where evidences of Arab irrigation works and of cultivation still attest to a once flourishing agricultural condition, without appealing to more rapidly destructive principles for the change.
Everywhere are evidences of water and wind erosion, of desiccation and differential weathering.
A The spores are capable of germination at once, or they may be kept for months and even years, and are very resistant against desiccation, heat and cold, &c. In a suitable medium and at a proper temperature the germination is completed in a few hours.
This was, however, more probably due to the deterioration of the country through desiccation, which has forced the settled population farther westward, where Sana became the centre of the later Himyaritic kingdom.
Lakes of the broad type are of moderate depth, the deepest sounding in [[Victoria (disambiguation)|Victoria ]] being under 50 fathoms. Apart from the seasonal variations of level, most of the lakes show periodic fluctuations, while a progressive desiccation of the whole region is said to be traceable, tending to the ultimate disappearance of the lakes.
Xxiii.) as to the characteristics of the former flora of the Tianshan, and the changes it has undergone in consequence of the extremely rapid desiccation of Central Asia, must be carefully borne in mind in all speculations founded upon the testimony of language as to the original home of the Aryans.
Of the highly developed civilizations which grew up and flourished in Bactria, Bokhara and Samarkand the last survivals are now undergoing rapid obliteration with the simultaneous desiccation of the rivers and lakes.
It fills a shallow depression which is drying up with astonishing rapidity, so that the process of desiccation can be shown on surveys separated by intervals of only ten years; large parts of it, like Aibughir Gulf, have dried up since the Russians took possession of its shores.
While the Sea of Aral remained in connexion with the Caspian, the desiccation of the Lake Balkash basin, and its break-up into smaller separate basins, were already going on.
But the gradual desiccation of the country resulted 4 For ampler information, see N.
Pp. 180, 339, and 488; Farmer, " Observations on the Effect of Desiccation of Albumin upon its Coagulability," ibid.
There is evidence of the increasing desiccation of the whole country north of the forest belt.