April 30, 1903] 



NA TURE 



607 



the neighbourhood of the gut, and which later on, 

 becoming connected with the gut, laid the foundation 

 of an important organ, the coecum. 



Excretory Organs, p. 437. — The author favours 

 Boveri's hypothesis of the evolution of the archinephric 

 duct, but with an almost fundamental modification. 

 However, this explanation, being inapplicable to Cyclo- 

 stomes, leads to new difficulties and further doubts, 

 which partly undo what has been elaborated just pre- 

 viously. H. Gadow. 



THE WORK OF MARIGNAC. 



Qiuvres completes de ]. C. Galissard de Marignac. 

 Tome ii., 1860-1887. Pp. 839. (Paris : Masson and 

 Co., n.d.) 



IT is by no means an easy task to give an intelligible 

 account of the labours of such an industrious 

 and versatile worker as Marignac was. An outline of 

 his life, written by M. Ador, his son-in-law, who edits 

 the two large volumes of his republished work, has 

 already been noticed in these columns. It now remains 

 to deal with his researches, of which only a sketch 

 has previously been given. 



The three main lines of investigation treat of (1) the 

 rare metals of their compounds, (2) crystallographic 

 measurements, and (3) thermal chemistry. Under the 

 first heading, we find memoirs on beryllium, lantha- 1 

 num, didymium, yttrium, erbium, niobium, tantalum, 

 " ilmenium," zirconium, mosandrum, and ytterbium, 

 the last a discovery of his own. The final article in the 

 book, published in 1887, is a criticism of Sir William 

 Crookes's paper " On the Genesis of the Elements "; 

 Marignac is not disposed to accept the interpretation 

 which Crookes places on the different spectra of suc- 

 cessive fractions of " yttrium," viz., that a gradual 

 separation of an element into parts endowed with 

 different properties has taken place ; he rather inclines 

 to attribute the varying spectra to the accumulation 

 at each end of fractions of impurities, each of which 

 has the power of profoundly influencing the spectrum 

 of the real yttrium. 



The equivalents of no fewer than twenty-eight ele- 

 ments were determined by Marignac ; and at the end 

 of the book a comparison is made between the values 

 found by him and the table of the International Com- 

 mittee of 1403. The correspondence between the two 

 is very striking; indeed, in no fewer than fourteen 

 instances, the numbers are almost identical. It is 

 strange, however, that Stas found for the atomic weight 

 of iodine the number 126-85, while Marignac agrees 

 more nearly with later determinations by Ladenburg 

 and by Scott. In stating his results, Marignac is 

 always modest. He writes : — 



" Je puis bien reconnaitre, apres avoir etudie le beau 

 travail de ce savant, qu'il a apporte, dans ses experi- 

 ences, des soins infiniment plus minutieux que ceux 

 que j'avais cru devoir prendre." 



Nevertheless, in almost all cases, the agreement with 



Stas is a very close one. He is by no means convinced 



that Prout's hypothesis is put out of court by Stas\ 



researches; he draws attention to the fact that while 



NO. 1748, VOL. 67] 



the mean variation from whole numbers of the atomic 

 weights determined by Stas should be about 0-5, it is 

 only 0.103, even if chlorine be included ; and if chlorine 

 be rejected, it is reduced to 0-068. 



From time to time, Marignac wrote criticisms of 

 notable papers recently published; and in many in- 

 stances he repeated the work of the authors. His 

 remarks were always gentle and kindly, hence he never 

 was drawn into controversy. Yet he bore his share 

 in attempting to solve the questions of his day; he 

 published many papers relating to dissociation ; the 

 most noticeable deals with the specific heats of gaseous 

 ammonium chloride, mercuric chloride, and sulphuric 

 acid, and the heats of volatilisation of these bodies. 

 The latter are naturally high, for they include the heat 

 of dissociation. Marignac's criticisms are, however, 

 sometimes a little naive; for example, after drawing 

 attention to Andrews's and Tait's observation that the 

 volume of ozonised oxygen is increased permanently by 

 raising its temperature to 230 , he remarks :— 



" Or, une condensation aussi considerable que celle 

 qui resulterait des experiences de MM. Andrews et 

 Tait eut et£ un fait trop saillant et trop important pour 

 echapper a ces habiles chimistes (MM. Fremy et 

 Becquerel) ou qu'ils n'en fissent pas mention." 



If this species of argument were permitted, the 

 progress of science would be slow. 



Marighac's crystallographic measurements are very 

 numerous, and were evidently made with the greatest 

 care ; they should form a valuable storehouse of facts, 

 when our knowledge of the relation between the forms 

 of matter and its constitution has been further de- 

 veloped. 



Among his researches on thermal chemistry, be- 

 sides those relating to anomalous vapour-densities, 

 Marignac devoted much time to the investigation of 

 the specific heats, densities, and expansion of solutions. 

 Like all his work, it is careful and exact, but led to 

 no important conclusions. 



Enough has been said to give the reader an idea 

 of the enormous productivity of Marignac. In his 

 own field, that of the rare earths, he is probably un- 

 surpassed as an investigator, and in issuing this col- 

 lection of his memoirs, M. Ador has erected to him a 

 monument " aere perennius." W." R. 



IRRIGATION IN THE WESTERN STATES OF 

 AMERICA. 

 Irrigation Institutions. A Discussion of the Economic 

 and Legal Questions created by the Growth of 

 Irrigated Agriculture in the West. By Elwood 

 Mead, CE. Pp. xi + 392. (New York: The Mac- 

 millan Company; London: Macmillan and Co., 

 Ltd., 1903.) Price 5s. net. 



THIS work was originally prepared for a course of 

 lectures on the institutions and practice of irriga- 

 tion for the University of California. The author is of 

 opinion that the land in the United States that has 

 hitherto been relied on to meet the demands of the 

 nation's growth will not much longer be available for 

 this purpose, so rapid has been the increase ' • e 



