214 



THE TROPICAL AGRICULTURIST. 



[September i, 1884. 



those of tobacco are by some Europeans ; the effect is that 

 ot a gentle stimulant and anti-narcotic. This plant is only 

 found in the south-western regions, and its use is limited 

 to them. 



The Pearl Fisheries of Arabia alone add to the com- 

 mercial riches of the country. They commence at the 

 islands of Bahreyn, which lie immediately off the Arab 

 shore, near the centre of the Persian Gull, and continue 

 east and south along the district of Katar for a distance 

 of nearly 2,000 miles, after which the banks are lost in 

 deep soundings. The most productive shoals are those 

 between the islands of Halool, and the coast of Katar ; 

 the fishing season commences with the spring, and lasts 

 all through the summer. Most of the villages along the 

 coast are wholly inhabited by divers, Arabs and Negroes, 

 who by long practice can remain under water a space of 

 two minutes at a time ; the depth they reach does not 

 exceed 15 fathoms, and generally falls much short of it. 

 The oysters are opened on shore, and the pearls carefully 

 sorted and counted by officials stationed for the purpose 

 as a heavy duty equalling 20 per cent of their value, is 

 levied on the spot, though no further dues are taken 

 on exportation. Some of the pearls are of great size and 

 value. The total annual produce is roughly estimated at 

 about £200,000, but probably exceeds that sum; a port ion 

 goes to India; another portion up Gulf to Baghdad, whence 

 it is distributed over Syria, Turkey and Persia. The divers 

 themselves are the worst off, as their occupation induces 

 various congestive diseases and premature old age. 



Pearls are found, too, in other bivalve shells of these 

 seas and are extensively sold, though at a lower price than 

 those of the oysters. Mother-of-pearl is also common, and 

 is an ordinary article of export, especially to Syria and 

 Egypt, so are also occasionally the corals, and ornamental 

 shells with which these seas abound. 



Of the revenues of Arabia it would be difficult to form 

 anything like a correct estimate. Palgrave has stated the 

 yearly receipt of the Nejdean, inclusive of the tribute then 

 (1862) paid into it by Bahreyan and the west of Oman, 

 to be nearly £106,000j sterling — no very large sum. 



The revenues of Oman itself, then iu a comparatively 

 prosperous condition, are estimated by the same author 

 at nearly ten times the amount, but may possibly have 

 been over-rated by him as those of Yemen were perhaps by 

 Niebuhr. Oertainly the general condition of these pro- 

 vinces — the restricted character of the cultivation and the 

 evident poverty (not absolute want, indeed, for that is 

 rare) of the greater number of the inhabitants — do not 

 convey to the visitor the idea of large national wealth or 

 extensive resources. There cau, however, be no doubt that 

 both the coast districts of Arabia, in their varied and valu- 

 able products, and the central plateau, with its palm- 

 groves, well irrigation, and wide pasture lauds, might, 

 under a judicious administration become the sources of 

 much greater revenues, both public and private, than is 

 now the ease. The mines, too, in the Metamorphic dis- 

 tricts of Yemen and Oman, remain yet to be properly 

 worked. As for the desert proper, which, as we have 

 seen occupies^aboutjone-third of the Peninsula, it must, like 

 the ocean of* Ghilde Harold, remain what it is to the end 

 of time. 



THE CIRCULATION OF SAP. 



Although plants have no general circulation like that 

 exhibited in the higher animal life, it is true that each 

 living cell has a circulation interesting in the extreme, when 

 Watched through th< mici scope, as it may be in the leaves 

 of the fresh-water tape grass. Here the sap may be seen 

 to circulate in a steady liow around each cell, carrying with 

 it small particles or gVeeu grains. The protoplasm under 

 the cell wall where this movement takes place is a sub- 

 stance having the same composition as the flesh of animals. 

 But these cell walls are not a barrier against the fluids 

 taken up by the roots, which are carried through the stems 

 of the topmost leaves of the loftiest hough ; thence, the 

 sap takes a downward movement through the cambium layer 

 and circulates throughout the plant or accumulates 

 wherever a deposit is being laid up for future use. The rise 

 of sap is quite rapid iu a leafy and growing plant on a 

 warm dry day, as may be seen from the amount of 

 water it is constantly exhaling from the foliage ; this 



loss is supplied by the absorption of water through th e 

 roots, otherwise the plants would die from thirst. Th e 

 cells of the roots are filled with a much denser sub- 

 stance then the outside moisture, and this moistur 6 

 is naturally drawn into them. While the leaves are 

 throwing off water, in the form of vapor, there is 

 left behind all the earthy and organic matter ; this in- 

 creases the density of the sap iu the cells of the leaf, 

 which draws upon the thinner contents of the cells of the 

 stalk, these upon those below, and thus the action con- 

 tinues down to the roots, which causes a flow from the 

 roots to the leaves. In a somewhat similar way the 

 elaborated sap is attracted toward any growing part, as 

 the bud, and here it is consolidated into fabric or pro- 

 ceeds to the tubes, etc., where it is changed into starch. 

 To make a distinction between elaborated and crude saps, 

 it may be well to remark that the latter is the water 

 absorbed by the roots and carried to the leaves of the 

 plant, while the former is the result of an extensive cir- 

 culation through the plant's cells. 



The wood of growing plants when cut from near the 

 surface hasbeen known to contain nearly 50 per cent of water, 

 and a still greater proportion in young twigs with a living 

 pith has been found. Interesting experiments testing the 

 amount of the flow of sap from different trees have brought 

 to light the fact that the birches yield an immense amount, 

 and an instance is recorded of a paper birch fifteen inches 

 in diameter flowing, iu less than two months, 1,486 pounds, 

 It has been supposed that the grape would bleed more 

 freely than any other species of plant, but this is not the 

 case ; it really bleeds but little. In regard to tapping 

 sugar maple trees it has been clearly indicated by actual 

 test that the proper method is to "insert the spout on 

 the south side as the sap will flow earlier, and more 

 abundantly than on the shaded side, and the late sap is of 

 little value for sugar. It has also been ascertained that 

 an increased number of spouts in a tree will increase the 

 quantity of sap obtained, though it is likely to contain 

 a less amount of sugar. The sap of the sugar maple con- 

 tains from two to three per cent of sugar while that of 

 the wild grape vine is almost pure water, and it has been 

 found in the late spring to contain no sugar, glucose, or 

 starch. While it is evident that the flow of sap in some 

 plants and trees is dependeut upon root absorption, it has 

 been shown that the rise and flow of maple sap is not 

 directly caused by the activity of this absorbent power. 

 There is a much slower movement of sap in the heart of 

 a tree than in sap-wood, which is probably due, in part, 

 to the fact that the old wood is more dense. The sap 

 is separated from the cellulose of the wood by the cold, 

 and under ordinary conditions gradually re-absorbed. The 

 bleeding may be regarded as a sort of leakage from the 

 vessels of the wood, which is probably increased by the 

 elastic force of the gases present. — Indian Ayriculturisf. 



Mr. J. Ferguson, of the CegUm Observer and Tropical 

 Agricultwrist (whose woik on "Ceylon,'' published by 

 Sampson Low & Co., was recently the subject of 

 favourable notice iu our columns), has lately come 

 home on furlough, travelling from Ceylon by way of 

 the Straits Settlements, Hongkong, and Canton in 

 China, Nagasaki, the Inland Sea, Kob6 and Yokohama, 

 as well as Tokio in Japan, and thence across the Pacific 

 to America. Mr. Ferguson spent some seven weeks 

 in travelling thorough America, including California, 

 Utah, Kansas, Chic g >, Toronto (Canada), and theme 

 through the Eastern and Southern Stite* as far south 

 as Florida, where (as well as in California) sub- 

 tropical agriculture was the subject of observation. 

 At a time when so much hit rest as to the future of 

 the planting industry, especially in tea, in Ctylou is 

 felt in mercantile and banking circles, it is well to 

 have so good an authority at hand to refer to as 

 this gentleman. A second edition of the standard 

 work, now called "Ceylon in 18 Q 4," we see is an- 

 nounced by Sampson Low & Co. Mr. Ferguson returns 

 ere long to his work iu Colombo, which city is likely 

 to become the centre for the information to the planters, 

 both of the east and west, through the pages of the 



Tropical Agriculturist.— European Mail. 



