April 6, 1888.] 



SCIENTIFIC NEAVS. 





Astronomy for Amateurs : a Practical Man ital of Telescopic 

 Research in all Latitudes adapted to the Powers of 

 Moderate Instruments. Edited by John A. West- 

 wood Oliver. London : Longmans, Green, and Co. 

 Scattered through the world are numerous people who 

 possess telescopes of more or less power, and most of 

 these instruments must from time to time be employed 

 for star-gazing ; but very little work of importance is done 

 with them. A few enthusiastic observers have made 

 themselves a world-wide reputation by devoting special 

 attention to some branch of astronomy, but by far the 

 greater number of amateurs content themselves with 

 occasional peeps at planets, nebulae, etc., and make no 

 endeavour to carry on a special line of research. Probably 

 this supiness is not due to lack of enthusiasm, but to the 

 fact that they do not know what to do, or what requires 

 to be done. We welcome, therefore, this work which 

 Mr. Oliver has edited ; it discusses what has been done 

 in various branches of astronomy, and indicates the points 

 on which further information is required, and which can 

 be studied with advantage by the possessors of telescopes 

 of moderate size. Sir Howard Grubb contributes a 

 paper dealing with the points to be attended to in pur- 

 chasing, testing, adjusting, and taking care of a telescope. 

 An article on the sun is written by Mr. E. W. Maunders, 

 of the Greenwich Observatory. It is devoted solely to 

 observations of phenomena shown by a telescope on the 

 surface of our luminary ; in an appendix he describes 

 the method of calculating the area and the heliographic 

 latitude and longitude of a spot. As, however, the areas 

 and positions of spots are obtained at the Royal Obser- 

 vatory from photographs of the sun's surface taken at 

 stations in various parts of the globe, it seems to us an 

 unnecessary reduplication of work for private observers 

 to undertake it, especially as their results are not likely 

 to be as accurate. From the chapter on the moon it 

 appears that, in spite of the careful scrutiny to which our 

 satellite has been subjected, there are still many points 

 on which further information is required. Mr. W. F. 

 Denning, well-known for his work on the planets and 

 meteors, is the writer of an article on the planets ; and 

 here, again, we are reminded there is a wide field of work 

 for the careful observer. An account of the precautions to 

 be taken in observing double stars is given by Mr. S. W. 

 Burnham, while Mr. J. E. Gore has compiled a list of 

 binary stars for which orbits have been computed ; 

 he also contributes an article on variable stars. The 

 subject of star colours is dealt with by Mr. W. S. Franks, 

 while Mr. T. W. Backhouse and Mr. J. Rand Capron 

 respectively write on stellar distribution and auroras. 

 We would strongly urge all amateur astronomers, even 

 if they only possess a good pair of opera-glasses, to obtain 

 this volume, as from it they will learn what work lies 

 within the power of their instrument, and may even be 

 encouraged to become observers. 



Electrical Instrument Making for Amateurs. By S. R. 

 Bottone. Whittaker and Co. 

 This little book is addressed to amateurs, who are 

 expected to have a very modest supply of tools and a 

 good deal of patience. The why and wherefore of the 

 action of the electric machines, and dynamos, seem to be 

 carefully avoided, and the preface states that " this work 

 does not profess to teach the science of electricity." We 



think in these days of smattering this is a mistake ; it 

 would be far better to put a book describing one form of 

 electric machine only, with a clear account of the principle 

 on which it acts, into the hand of a schoolboy, who could 

 set to work with a fair grasp of what he was going to do, 

 than to present descriptions of five electric machines, and 

 an electrophorus, and four dynamos, leaving him to take 

 his chance of understanding them, even if he succeeds in 

 constructing them and making them work. How many 

 owners of electric machines or induction coils have the 

 smallest knowledge of their action, and use them merely 

 as toys ; and if they are home-made, without such know- 

 ledge (and with a little patience and ingenuity they might 

 be put together by the help of this book), it can hardly 

 be said that a step has been taken in the right direction. 

 The author would " strongly recommend every student 

 to make an electrophorus, and not to rest satisfied until 

 he has fully mastered the theory of its action." Half a 

 page would have at least given him some hint towards 

 the solution of a problem which we do not think that one 

 " amateur " in a hundred would solve by the light of 

 nature. Instructions are given for the making of galvano- 

 meters, induction coils, etc., and several useful hints on 

 working glass plates and insulating are to be found. The 

 directions for graduating an ammeter are, however, quite 

 impracticable, and those for the voltmeter are little better. 



The Shell-Collector's Hand-Book for the Field. By J. W. 

 Williams, M.A., D.Sc, London: Roper and Drowley, 

 1888. 

 It is a pleasing duty to bring under the notice of our 

 readers a hand-book the aim of which is to supply 

 collectors of British land and fresh-water shells with 

 what has been long wanted by them, viz., a collection 

 of descriptions of recognised varieties, in addition to a 

 conspectus of the classes, orders, families, and genera, 

 and descriptions of species. Of the three introductory 

 chapters, those on the anatomy of a snail and fresh-water 

 mussel are good, and are written in a pleasingly clear 

 style, and the energetic student, with time at his disposal, 

 will find the lists of books of reference appended to 

 these chapters of great use. In the chapter on collecting 

 and preserving, sound advice is given, which many 

 collectors would do well to follow. We are surprised, 

 however, that the scoop is not recommended for taking 

 aquatic species, which is generally considered to be much 

 better for the purpose than a water-net, and we do not 

 think the removal of the confervoid growth so often found 

 upon shells is any improvement. Errors and omissions are 

 not altogether wanting ; in fact, a perusal of the 1 48 pages 

 of the book discovers far too many ; but we have no desire 

 to find fault, and will only mention that we looked 

 for several varieties oiArion atcr of which we could find 

 no mention, and these included the well-known var. 

 plunibca of Mr. Roebuck. The general plan of the book 

 is perhaps its chief failing. Bound in limp covers it is 

 essentially a pocket-volume, " for the field," but it is 

 seldom required to examine shells before home is 

 reached, and surely there was no need to keep the 

 book within pocket size, when notes on habits and dis- 

 tribution would have so greatly enhanced its value. We 

 are glad to find that the nomenclature adopted is that 

 which is understood by the rank and file of shell- 

 collectors — name changes should never be introduced 

 in a little hand-book like the present— and, with the ex- 

 ception that Moquin-Tandon's subgeneric title Euliinax is 

 used, the young collector will find nothing with which 



