424 



NA TURE 



[April i, 1922 



The task of feeding them falls entirely upon the 

 female, though the food is always brought to her 

 by the male, who also feeds his mate. He brings 

 her but two meals daily, one just after sunrise, the 

 other just before sunset. But these are supplemented 

 by small portions taken from the supply brought 

 for the young. Titlarks formed 90 per cent, of the 

 prey, which included also skylarks, thrushes, ring- 

 ousel, and snipe. Invariably the victims were 

 beheaded and deplumed at a distance from the nest. 

 At times, however, some were brought partially 

 plucked, when the female would give each youngster 

 in turn a mouthful of feathers only, the mother her- 

 self partaking, apparently for digestive purposes. 

 Mr. Rowan was never able to satisfy himself as to 

 the means by which the transference of the prey 

 from the male to his mate was effected. As he hove 

 in sight she would fly out to meet him, then at 

 incredible speed pass beneath him and seize the 

 prey. But whether it was dropped, or snatched 

 from his talons, he could never discover. 



Shell-Structure in Foraminifera. — Prof. W. J. 

 Sollas, from an examination of the widely known Car- 

 boniferous foraminifer, Saccammina Carteri, has been 

 led to make a detailed study of the shells of calcareous 

 foraminifera in general [Quart. Journ. Geol. Soc, 

 London, vol. Ixxvii. p. 193, 1921). He shows that 

 the mineral in IJoth perforate and imperforate types 

 is calcite, and that some imperforate species have a 

 vitreous appearance. In the ordinary vitreous fora- 

 minifera the shell is composed of minute prisms of 

 calcite set with their longer axes perpendicular to 

 the wall ; in porcellanous types, no such regularity 

 is shown by the calcite " fibrils " that are present, 

 and these sometimes pass into a granular structure. 

 Blind canals, but not perforations, occur in the walls 

 of Peneroplis, and it is suggested, from observations 

 by Douville, that the alleged perforations of the 

 characteristic Upper Palaeozoic genus Fusulina may 

 be of the same nature. The author removes " Sac- 

 cammina " Carteri from the arenaceous to the 

 calcareous imperforata, and points out that the 

 mosaic structure of its shell finds a counterpart in 

 Spirillina. He proposes that the genus should now 

 be called Saccamminopsis, 



Climates of the Past. — In a brief but illuminating 

 review of the cHmates of past geological periods. 

 Dr. Charles Schuchert [Amer. Journ. Sci., vol. cci., 

 p. 320, 192 1) concludes that climatic changes were 

 " very slight during the middle parts of the geologic 

 periods [as defined by faunistic changes], when the 

 world has almost no temperature belts ; and variably 

 greatest during the earliest and latest parts. . . . 

 To-day the variation on land between the tropics 

 and the poles is roughly between 110° and -60° F., 

 in the oceans between 85° and 31° F. In the geologic 

 past the temperatures for the greater parts of the 

 periods of the oceans was most often between 85° 

 and 55° F., while on land it may have varied between 

 90° and 0° F. At rare intervals the extremes were 

 undoubtedly as great as they are to-day." The 

 author believes that for long epochs the greater part 

 of the earth has had an almost uniformly mild 

 climate, with no winters ; but he opposes F. H. 

 Knowlton's view that there was a continuous non- 

 zonal arrangement of climate prior to the Pleistocene 

 period. It will be remembered that Dr. Schuchert 

 (see Nature, vol. cvii. p. 501) connects the limits 

 between geological periods with diastrophic events, 

 and the influence of these, when they are of world- 

 wide importance, is probably effective in breaking 

 up the conditions that tend to equality of climate. 

 In the same journal (vol. ccii. p. 187) Mr. Knowlton 



NO. 2735, VOL. 109] 



replies to Dr. Schuchert, and also to a criticism by 

 Prof. Coleman. He relies on a dual control of 

 temperature in geological times by the internal heat 

 and also by the sun, and believes that the earth was 

 until recently surrounded by a cloud-envelope, 

 maintained by the internal heat, but diminishing 

 from time to time when this heat declined. Few 

 geologists will agree with him in minimising the 

 evidence for the occurrence of occasional epochs of 

 clear air and unchecked sunlight. Surely, moreover, 

 deposits of gypsum are not usually regarded as 

 products of marine lagoons, and the difficulties raised 

 on this matter by Mr. Knowlton seem mostly of his 

 own making. If his cloud-envelope could be regarded 

 as a reality, a good deal of biological as well as 

 physical evidence would have to be reconsidered. 



Rainfall in Latin America. — The United States 

 Monthly Weather Review for October 1921 contains 

 articles by Mr. E. Van Cleef and Mr. B. O. Weitz on 

 " Rainfall Maps of Latin America," " Some Illus- 

 trative Types of Latin- American Rainfall," respec- 

 tively. The first article, when dealing with the 

 plotting of the data, mentions that the observations 

 are not always for corresponding periods, and as no 

 correction has been made for this the results are not 

 always comparable, although in drawing the isohyets 

 considerable judgment has been used. The author 

 makes no pretence that the maps give a final state- 

 ment of the distribution of rainfall, and he states 

 that it may require another 75 years or longer before 

 there is sufficient accumulated data to produce an 

 accurate map. Average maps are given for the year 

 and for the summer and winter. In addition to these 

 there are short accounts explanatory of the rainfall 

 over certain areas, viz. in Mexico, Central America 

 and Panama, and South America. The problem 

 of the llanos of Columbia and Venezuela is dealt 

 with, and it concludes with the statement that the 

 cause of the apparent dryness of llanos and the 

 absence of trees in interstream areas must remain 

 in the hypothetical stage. The second article is 

 illustrated by graphs showing the annual and monthly 

 averages of rainfall at 25 representative stations in 

 Latin America. The article concludes by stating 

 that the discussion has not covered the complexity 

 of all rainfall types but only those which are most 

 essential. A praiseworthy attempt has been made 

 to associate the climatic controls with various rainfall 

 types. 



The Claude Ammonia Process. — In the Claude 

 process, in which ammonia is synthesised from 

 nitrogen and hydrogen under a working pressure of 

 1000 atmospheres, the heat produced in the reaction 

 was at first removed by circulating molten lead round 

 the reaction tubes. This was found, however, to 

 lead to undue strain in the tubes leading to fractures 

 (see Nature, February 16, p. 219), and a new method 

 has been adopted, an account of which is given by 

 M. Georges Claude in the Comptes rendus of the Paris 

 Academy of Sciences for March 6. Uniformity in 

 temperature of the reaction tubes is secured by 

 jacketing them with asbestos or kieselguhr. The 

 heat of combination of the two gases is utilised to 

 heat the entering gas to about 500° C. No pre- 

 liminary heating is now required, and the tubes are 

 so proportioned that the gases are heated in the 

 catalytic tube gradually as required by the reaction. 

 Among other advantages, the head of the tube carry- 

 ing the connecting screws is almost at room tempera- 

 ture and the external tube supporting the high 

 pressure is only heated to a high temperature at one 

 end, which can be appropriately strengthened. The 

 method works excellently in practice and has been 

 in use for over twelve months. 



