266 



NATURE 



[March 2, 1922 



to measure the angular width of each stone from the 

 observational base^ and both the side measures and the 

 average measures thus obtained should be studied. 

 The following are averaged measures : — 



The average angle for the series is about 89° 30'. 

 In two instances, side alignments form perfect right 

 angles. In other instances it seems highly probable 

 that the angular width of a stone was utilised for 

 two alignments. Thus, of the side measures averaged 

 as N. 42° W., the one on the north side of the stone 

 is 38° and the one on the south side is 46°. By the 

 table of solstitial azimuths for lat. 57° N. given on 

 page 381 of "Stonehenge" (sec. ed.), 46° would be 

 sunset at the summer solstice with a horizon of 2° 

 high, and 38° would be sunrise at the winter solstice 

 with the horizon a trifle higher. 



It is a great thing to know that the position of each 

 stone in a Pictish circle is, or was intended to be, at 

 right angles to some other position. If the observa- 

 tional base of other types of circles could be discovered 

 it is extremely likely that the same fundamental 

 principle would be found applied. Given a number of 

 rectangular alignments, with horizon measures, it is 

 practically certain that for each circle a star cast, like 

 that of actors in a drama, could be made out, making 

 the determination of the period involved comparatively 

 easy. 



Without horizon measures, the solar alignments of 

 the Dunecht circles are easily recognisable. Judging 

 by the one complete circle described, we are warranted 

 in assuming that both the May-year and the solstitial 

 year are provided for. Regarding the base line as of 

 first importance, we have May-year, solstitial, and 

 stellar circles of one and the same cultural type. For 

 an explanation of this variety in unity we need, for 

 one thing, a new survey of all the^Pictish circles on the 

 plan suggested by Dr. Browne. John Griffith. 



Thorpe's Dictionary. 



A Dictionary of Applied Chemistry. By Sir Edward 

 Thorpe. Assisted by Eminent Contributors. Vol. 

 2 : Calculi to Explosion. Revised and enlarged 

 edition. Pp. viii + 717. (London : Longmans, 

 Green and Co., 1921.) dos. net. 



THE '' Dictionary of Applied Chemistry " has now 

 become so indispensable to workers in pure 

 as well as in applied chemistry that it can be stated 

 without fear of contradiction that no library either 

 NO. 2731, VOL. 109] 



in the university or in the works can be regarded as 

 complete without it. The appearance of the second 

 volume of the new edition following so closely on that 

 of the first will therefore be welcomed, and will be 

 taken as an indication that the remaining volumes will 

 be published with equal rapidity. The first feature 

 which is noticeable in the new volume is the decrease 

 in size and the increased handiness compared with 

 the corresponding volume of the last edition. This 

 result has been attained by reducing the number of 

 pages by about eighty and by using a thinner paper, 

 the general effect being to produce a volume which 

 can be held in the hand readily without fatigue. It 

 follows, although it is not specifically stated, that the 

 pubHshers intend to issue the dictionary in six or more 

 volumes instead of the five which have hitherto 

 sufficed. 



The subject-matter in the volume under review 

 therefore comprises part of that issued in vol. i of the 

 last edition and part of that which appeared in vol. 2. 

 The last edition of the dictionary was reprinted in 

 1917 from the revised edition of 1912, but despite the 

 comparatively short time which has elapsed — a period 

 during which little scientific work was done — it has 

 been found possible to introduce much new matter; 

 this is shown by the fact that the subjects dealt with 

 in the present volume occupy 717 pages, whereas in 

 the last edition they filled 547 pages only. 



On the whole there is little call for criticism. The 

 article on carbohydrates — one would like to see this 

 name abandoned because, obviously, the sugars of the 

 rhamnose group, Z^-^<f)^, are not carbohydrates — by 

 E. F. A. is altogether admirable and stands out by 

 itself as an illustration of what can be done by a master 

 of his subject to make a highly complex chapter in 

 organic chemistry interesting to expert and lay-reader 

 ahke. On the other hand, the article on camphor is 

 very disappointing. It is difficult to understand what 

 useful purpose can be served by publishing an article 

 on the chemistry of this substance which does not 

 contain one single graphic formula. Had this edition 

 been pubHshed thirty years ago there might have been 

 some justification for the inclusion of this article. 

 The articles on carbolic acid and cellulose remain 

 practically unaltered ; it is doubtless too soon to expect 

 to find a full description of the many important uses 

 to which these substances and their derivatives were 

 put during the war. 



The article on chlorine has been entirely rewritten 

 by H. B., and is an exhaustive account of this 

 element. It contains a vigorous reference to the use 

 of poisonous substances by the Germans during the 

 war, and gives a list of some of those employed. One 

 would like to have seen, however, an article on chemical 



