Notices respecting Sew Boole*. ^81 



A table of contents, pp. xiii and xiv, and an index, pp. 551 to 552 

 make the book easily consulted. 



The preparation of the tables in a volume such as this represents 

 an enormous amount of labour of a land calculated to damp the 

 ardour of any but the most enthusiastic workers, and Dr. Buchan 

 and Mr. Omond well deserve the thanks of meteorologists. They 

 are to be congratulated on the beautifully clear way in which the 

 tables are printed, and on the success of the various devices for 

 guiding the eye to take in the prominent features. The reader of 

 the Ben Kevis " logs '"' must also bear a tribute to the great zeal 

 shown by the observers at the summit. The freezing-up of instru- 

 ments, blocking by snow, and other exceptional conditions, render 

 the use of ordinary self-recording apparatus impossible, so that 

 all the hourly records— except those of sunshine — are from eye 

 observations. In the. winter months, during high gales and 

 drifting snow, few people would envy the observer whose duty 

 takes him out of doors in the midnight hours. When, it comes to 

 a critical estimate of the value of the observations, there is a little 

 more room for doubt. The non-instrumental estimate of such a 

 constantly fluctuating element as wind-force, the record of rainfall 

 or melted snow during storms, the use of the sunshine recorder in 

 alternating clear and snowy or foggy weather, are attended by 

 uncertainties from which the records at low-level stations are 

 comparatively free. Such sources of uncertainty should, however, 

 be largely eliminated when it comes to mean monthly or annual 

 diurnal variations. In the comparison of the data at the base and 

 the summit there are uncertainties arising from the great difference 

 in the environment of the two stations. The station at the base 

 has its wind and even its sunshine record considerably interfered 

 with by surrounding high grounds ; whilst some of the records at 

 the summit are influenced by the want of symmetry in the shape 

 of the mountain, there being an enormous precipice on one side of 

 the observatory, at no very great distance. This want of symmetry 

 must add to the difficulty of judging how far meteorological con- 

 ditions at the summit are comparable with those that would exist at 

 the same level in the free atmosphere if the mountain were non- 

 existent. In some of the discussions in the latter part of the 

 volume evidence of greater familiarity with physical principles and 

 results, and with the theory of instruments, would give the reader 

 more confidence that the point of view selected is the one most 

 likely to lead to a clear issue. There seems a slight slip in the 

 theory of the table on p. 545 for eliminating from diurnal variations 

 any " non-cyclic " change taking place progressively. The table 

 ascribes to an interval of 23 hours the change that really answers 

 to 24. The consequent error would, however, very seldom be of 

 practical moment. C. C. 



