y title 26, 1879] 



NATURE 



191 



authorities are advised that they can ruin all the gas 

 interests without the distribution of any compensation 

 whatever. Surely the enormous capital sunk by the 

 public in gas enterprise deserves some consideration 

 from its representatives in Parliament assembled. Are 

 our vestries and corporations so immaculate that they 

 are to have entire control of our supplies of water and of 

 light ? Why not give them the supply of food and of 

 heat ? The line must be drawn somewhere, and it is well 

 that Parliament should hesitate in the complacency with 

 which it now thrusts on irresponsible communities the 

 distribution of vital necessaries. 



The only sphere in which electricity has made itself 

 useful and practical as an illuminant is in our lighthouses, 

 and though it is eminently adapted for nautical purposes, 

 as ordinary ships' lights, or to illuminate the sails of a 

 ship, the Report is silent on the point and on the absurd 

 restrictions which have been placed by the Board of 

 Trade on its use at sea. 



The statement that the energy of one-horse power 

 when converted into gas-light only gives 12-candIe power 

 and into electric light 1,600 candle power is startling if 

 true. Without the evidence before us on which this 

 statement is made we cannot well contravene it, but it 

 seems based on some fallacy. We remember seeing 

 somewhere, but cannot recall where, a somewhat similar 

 estimate, but it was based on the assumption that the 

 whole of the coal was consumed in producing gas, and 

 no allowance whatever was made for the coke, tar, and 

 other products of distillation. Is it so in this instance ? 

 Though 3 lbs. of coal consumed in one vfa.y may give one 

 horse-power, and in another way 12-candle light, it by no 

 means follows that one-horse power is equivalent to 12- 

 candle gas-light — for in the case of gas we do not know 

 the remanent energy. 



The report fully confirms the opinion we have fre- 

 quently expressed that the electric light sensation was 

 due to a scare and not to any real progress or new dis- 

 covery made. The transmission of power for mechanical 

 purposes is foreign to the inquiry, and the suggestion that 

 currents used by day for mechanical purposes can be used 

 at night for illuminating purposes assumes what we only 

 wish were true, that there is no mechanical work done in 

 England in hours of darkness. 



The general conclusion arrived at is that we can do no 

 more with the electric light at present, but that we must 

 i do nothing to restrict its development. We did not 

 j require a Parliamentary Committee to tell us that. 



INDIAN GEOLOGY 

 A Manual 0/ the Geology of India. By H. B. Medlicott, 

 M.A., and W. T. Blanford, F.R.S. Published by 

 Order of the Government of India. (Calcutta, 1879.) 



THE appearance of this long-promised work marks an 

 epoch in the history of Indian science. In two 

 moderate octavo volumes (paged as one) and the map 

 which accompanies them, we have placed before us, in an 

 attractive and convenient form, the matured conclusions 

 of upwards of thirty years' systematic surrey of the 

 geology of our Indian possessions ; and now, for the first 

 time, the geological structure of India, or, at least, its 

 leading facts, may be mastered by the student at no 



greater cost of labour than is involved in a few days' study 

 of a well-arranged and thoroughly trustworthy manual. 



We are reminded almost in the opening words of the 

 preface, how many of those who have contributed to the 

 researches on which this work is based, have now passed 

 from among us. Stoliczka, J. G. Medlicott, the two 

 Oldhams, Williams, and Loftus are only a few of the 

 better known names among the many that for a longer or 

 shorter time have been borne on the rolls of the Indian 

 " Geological Survey," whose bearers lie in Indian grave- 

 yards, or beneath some modest tomb on the out-skirts of 

 an Indian village, or who finally have returned with 

 shattered health to the land of their birth, only to bring 

 to a close among their friends the last few enfeebled 

 months of their career. Of the earlier labourers in the 

 field, of those who witnessed the birth of the " Geological 

 Survey of India," and who three-and-twenty years ago 

 wielded their hammers in breaking open the secrets of 

 Indian rocks, but three still remain members of the 

 Survey Staff, and to two of these surviving members 

 whose names stand at the head of our article, we are 

 indebted for the present masterly summary of th'> common 

 labours of all. 



The contributions of the two authors to the joint work 

 are distinct, and in point of magnitude unequal. To Mr, 

 W. T. Blanford has fallen the lion's share of the labour. 

 Of the thirty chapters which (including the introduc- 

 tion) make up the work, Mr. Medlicott contributes ten, 

 viz., those on the metamorphic and azoic rocks of the 

 peninsula, and those on the geology of the Himalaya 

 east of the Jhelum, and on Assam. The remaining 

 twenty chapters, including the introduction, which deal 

 with all the fossiliferous and neozoic rocks of the penin- 

 sula, the geology of Sind, the Punjab and Burma, and 

 the Sivalik fauna generally, are the work of Mr. W. T. 

 Blanford. The map,^ which is printed in colours and is 

 on the scale of sixty-four miles to the inch, has been 

 compiled in the office of the Geological Survey, from mate- 

 rials in part unpublished. It professes to be only a pre- 

 liminary sketch map, and three small tracts in the penin- 

 sula, the greater part of the Bikanir Desert and Guzerat, 

 the Nepalese Himalaya, and Arakan and the adjoining 

 hill tracts are left uncoloured. But with these exceptions 

 it exhibits in as detailed a form as the scale admits of, 

 and with unquestionable accuracy, the extent and boun- 

 daries of the several formations, classed as Alluvium, 

 Upper and Lower Tertiary, Cretaceous, Jurassic, Triassic, 

 Carboniferous, Silurian, Submetamorphic, Metamorphic, 

 Granitic, Volcanic; and in the peninsular area, Upper 

 and Lower Gondwana, and Vindhyan, the meaning of 

 which unfamiliar and special classification we shall pre- 

 sently have occasion to notice. 



The subdivision of the whole region into a peninsular 

 and an extra-peninsular area is one of fundamental im- 

 portance, and, as such, is treated in the arrangement of 

 the manual. Geographically, the two areas are separated 

 by the broad unbroken alluvial plain which stretches along 

 the foot of the mountain zone from the mouths of the 

 Indus to those of the Ganges ; and geologically both in 



' A copy of this m.ip v/as sent for exhibition to the Gre.it Paris Exhibition 

 last year, but was probably seen by few. In fact, it was suspended in the 

 office room of the Indian department, avowedly for want of room. Mean- 

 while a conspicuous case in the centre of the transept was devoted to the 

 exhibition or Irdian pickles. 



