Notices respecting JSew Books. 243 



public, and what better way of doing so could there be than by 

 writing a short treatise on the use of the instrument ? In 

 observatories the astronomer looks upon his transit as the only 

 means at his disposal of ensuring that correctness of time without 

 which all his observations would be valueless. The price of the 

 instrument is now so reduced as to bring it within the reach of all 

 w r ho are anxious to attempt the feat of keeping all the watches and 

 clocks in their houses in accordance with Greenwich time, even if 

 they resemble the immortal Captain Cuttle's watch. In the general 

 description of the instrument, the directions given for the use of 

 the striding level, in which we are told to file away a little brass 

 " from the higher end" of something or other, are, to say the least, 

 a little vague. Nor is the description of the use of the vernier 

 couched in such language as to make its meaning at all clear. Eye 

 and ear observations are always difficult, but this difficulty is surely 

 much increased when we have to count the ticks of the same watch 

 with which we are noting the time of transit. We have never 

 tried the method recommended for obnating the roughness or want 

 of level of a pillar by the use of a greased sheet of glass, on the 

 surface of which " the instrument slides freely," and which is to be 

 levelled by means of " a little pool of water and two or three small 

 wooden wedges," but we should imagine that its adoption might 

 possibly lead to the necessity of purchasing a second instrument 

 from the maker. There are, however, many useful points in the 

 book. The Tables, which are published annually, will doubtless 

 be highly esteemed by those amateurs who possess a transit 

 instrument, but are not disposed to wade through the calculations 

 involved in the use of the Nautical Almanac, from which the 

 contents of the present little volume are computed. For every day 

 in the year we have the Greenwich Mean Time of Transit (as well 

 as the Altitude) of the Sun and of various suitably situated Stars 

 to '01 of a second ; while for alternate days that of the transit of 

 each of the chief planets is tabulated to the nearest minute. There 

 are also clear directions how to fix the transit instrument, and how 

 to find Greenwich or local time in any part of the world. In what 

 Mr. Clark calls his " Improved "Window Transit" we have a new 

 and handy form of the instrument, w T hich obviates the use of the 

 diagonal eye-piece, and, we should think, renders the taking of a 

 transit a much easier process than with the usual form. To 

 residents in country places, far away from a trustworthy clock, the 

 use of these tables and one of the author's instruments will save 

 much vexation and the loss of many a train. 



General Index to the First Twenty Volumes of the Astronomical Register. 

 By P. W. Leyakdek, F.E.A.S. London: Alabaster, Passm ore 

 and Sons, 1883 (pp. 82). 



It goes wdthout saying that such a work as this must be very 

 useful to a very large class of readers : even the non-astronomical 

 reader is interested in it. He might wish to learn how (Lord) 



