June 22, 1882] 



NATURE 



i/. 



of a work published at a small native press at a great 

 distance from the author. Still the misprints in this 

 work are quite unusually numerous, sometimes three in a 

 single line of French or German, sometimes four in a 

 single page of ordinary matter ; this throws some doubt 

 on the accuracy of the printed Tables (which cover about 

 130 pp. folio). The complete Report must have included 

 about 29 plates (constant reference being made to them), 

 but only three are published ; the absence of these plates 

 makes it often difficult, sometimes impossible to follow 

 the author's argument. Again, the want of uniform 

 transliteration of proper names causes difficulty in identi- 

 fying unfamiliar places, the same place being often spelt 

 in two or more ways (e.g. Shoaygheen, Shwaygheen, 

 Shwe'gyeen, &c). There is a too frequent use of local 

 words (e.g. ckoung = river, eng = lake, &c), and also of 

 odd un-English words (eg. divagation, prescinding, &c). 

 These are, however, trifling drawbacks compared with 

 the fact that the work is one of great value, combining 

 the results of unusual knowledge of the literature about 

 the Irrawaddi with probably unique practical knowledge 

 of the Irrawaddi Delta. 



The work contains three very distinct subjects : 1, the 

 question of the sources of the Irrawaddi (Parts I. and II.); 

 2, the hydraulic works on the Irrawaddi (Part III.) and 

 Nawoon Rivers (Part IV.) ; 3, the theory of the flow of 

 water in rivers (Parts III. and IV.). 



Sources of l/ie Irrawaddi. — Parts I. and II. form a 

 monograph on the vexed question of the lower course of 

 the great Thibetan River (Tsanpou or Sanpo) ; its upper 

 course from west to east within the heart of the Himalya 

 mountains has long been roughly known (by travellers' 

 reports), but its lower course beyond the Himalya is still 

 strangely obscure. The Indian Survey maps have long 

 shown the Sanpo as continuous with the Brahmaputra. 

 But the author adopts the view of the great French geo- 

 grapher, D'Anville (circa 1730), that the Sanpo is the 

 upper course of the Irrawaddi. He discusses at great 

 length the general features of the Thibetan plateau and 

 of the Brahmaputra and Irrawaddi valleys, especially as 

 to the distribution of mountain and valley, and as to rain- 

 fall and river discharges. The chief argument is that 

 just above the dtbouchute of the highest known large 

 affluent (the Mogoung), a little above Bhamo, at a dis- 

 tance of 800 miles from the sea, the Irrawaddi is still an 

 immense river 1000 yards wide and with a flood discharge 

 of over 1,000,000 cubic feet per second, and therefore 

 requiring a large drainage area above Bhamo. Now 

 within 100 miles above Bhamo, the five great rivers — 

 Brahmaputra, Irrawaddi, Salween, Mekhong, and Yang- 

 tse-kiang — are known to be contained within a narrow 

 strip of 200 miles width ; from this it would seem that the 

 sources of the Irrawaddi must be very distant (from the 

 want of numerous large affluents). By collating the 

 various travellers' accounts of the Sanpo, it is shown that 

 they are consistent with its being continuous with the 

 Irrawaddi. 



Most of this appears to have been written in 1S77. But 

 in 1877-7S the Indian Survey Department conducted 

 some special investigations on the question ; their ex. 

 plorers traced the Sanpo downwards to within about 100 

 miles of the nearest regular survey party then at work on 

 the affluents of the Brahmaputra near the limits of British 



territory ; this gap of 100 miles was left a terra incognita, 

 so that the question was still open to conjecture. After 

 some discussion of this later work, it is shown rather to 

 favour the author's earlier writings. 



Besides the main (geographical) argument there is 

 much interesting matter in these two parts on the geology, 

 meteorology, and some minor features of the Sanpo and 

 Irrawaddi basins. The want of a good detailed map is 

 much felt here in attempting to follow the geographical 

 argument. 



Hydraulic Works. — Parts III. and IV. deal chiefly 

 with the (engineering question of) Embankment AYorks 

 in the Delta of the Irrawaddi, intended for reclaiming the 

 rich alluvial land and for shutting out flood water. In a 

 practical sense this is much the rao;t important part of 

 the Report ; but in the absence of the plates it is impos- 

 sible to follow the great detail given. Still there is much 

 of general interest admitting of some notice here. 



Firstly, it is explained that most of the easily cultivable 

 land in British Burma having been already taken up, the 

 country — though apparently thinly populated — is actually 

 well populated over the only good land ; and that, to pre- 

 vent over population, what is now really wanted is more 

 land. In this view the reclamation of good land acquires 

 great importance. This work in some way resembles 

 that in the Mississippi Delta, with the important differ- 

 ence that the latter is a rich country with ample funds 

 for the prosecution of large works, whilst Burma is a 

 poor country without adequate means for the same. In- 

 deed, the history of the works as herein set forth is 

 throughout one of insufficient provision of funds for their 

 rapid prosecution, and sometimes even for their proper 

 repair ; this was very disadvantageous, as of all works 

 the timely repair of an embankment is perhaps the most 

 urgent, as its breach may be simply disastrous. 



In early days high floods on the Irrawaddi seem to 

 have been rare ; at any rate the floods of late years (1S68, 

 1871, 1S75, 1877, 1S79) have all risen considerably above 

 the highest supposed possible from local inquiry in 1862. 

 It seems possible that this is due partly to the gradual 

 destruction of the forests above, which causes the rainfall 

 to be more violent while it lasts and also favours its rapid 

 descent to the main stream, and partly to the erection of 

 the embankments themselves which confine the fl sorts tc 

 the main river. 



A very curious instance is noticed that the 1875 and 

 1879 floods were foretold by the Burmese astrologers. 



Flow of Water. — The uncertainty of hydraulic know- 

 ledge nowadays is well illustrated by the various opinions 

 of successive engineers on the rise that would ensue in 

 the river consequent on embanking it on both sides 

 throughout the Delta. It is said that Col. Stoddard 

 reported in 1869 that the rise would not exceed the 

 average of one foot, whilst the professional adviser of 

 Government considered that it might amount to 3 or 

 4 feet at Henzahda, and the author himself considered 

 from 7 to 12 feet a probable rise. It is obvious that 

 these results cannot be said to be any better than con- 

 jectural ; their discrepancy showing that the formulae in 

 use for such sort of calculation were (as too often 

 happens) inapplicable to the case in hand. The Govern- 

 ment naturally declined to sanction the project. 



The author then undertook an extensive series of direct 



