534 



NATURE 



[June 23, 192 1 



it had been the site of a building. A remarkable 

 piece of carved wood in the shape of a lintel, 

 which was found at a depth of 5 ft., has just been 

 secured for the Auckland Museum. In its centre is 

 represented a human figure "almost gorilla-like in 

 appearance"; it has a broad, wedge-shaped head 

 with projecting ears, small broad nose, and a large 

 oval mouth with small tongue. The body is small, 

 short, and squat. The outstretched hands of the 

 figure rest upon a perforated framework spreading 

 right and left, the ends of which each terminate in a 

 saurian-like head. Water-worn stones of the size of 

 a hen's egg which have human features carved on 

 them have also been found. The antiquity of these 

 remains, as well as their style and technique, would 

 appear to preclude their attribution to either Maori or 

 Moriori. 



The American .Association for the .Advancement of 

 Science, the National Academy of Sciences, and the 

 National Research Council have appointed small com- 

 mittees which held a joint meeting on April 9 last to 

 consider the problem of the conservation of the natural 

 resources of the United States (Science of June 3). 

 A resolution was passed recommending that the com- 

 mittees already in existence should function as a joint 

 committee on national conservation, and at subse- 

 quent meetings of the three organisations represented 

 the resolution was confirmed, and funds were pro- 

 vided for defraying the immediate expenses of setting 

 up an executive and secretarial ag^ency for the prose- 

 cution of the work. The main objects of the organi- 

 sation which is to be established are stated under five 

 headings ; first, to direct scientific research so that 

 it mav bear more directly on the problems of con- 

 servation, a consideration which will involve a wide 

 knowledge of the scope of any problem, and its re- 

 lation to the programmes of research in other fields 

 of work; secondly, the collection of data relating to 

 natural resources, and their interpretation in relation 

 to the economic, industrial, and social welfare of 

 different regions, and of the nation as a whole ; 

 thirdly, to introduce the principles of conservation 

 into the curricula of educational institutions ; fourthly, 

 to lead a campaign of popular education in the mean- 

 ing of conservation ; an^ fifthly, to correlate the 

 efforts of existing agencies which are striving for 

 conservation in their own particular fields. We shall 

 await with interest the development of this scheme 

 for economising the natural resources of the United 

 States. 



Dry weather has been persistent in England during 

 several months, and now that we are more than half- 

 way through the first month of summer the absence 

 of rain has become serious. The observations at 

 Greenwich, which very fairly represent England, 

 show that the conditions are most exceptional. The 

 Greenwich rainfall was below the normal for each of 

 the eight months from October, 1920, to May, 192 1, 

 and compared with the average for 100 years the 

 deficiency of the period is 6-21 in. — approximately 

 equal to the normal rainfall for the four months 

 February to May. There have, however, been only 

 two months, November and February, with the rain- 



NO. 2695, VOL. 107] 



fall less than an inch. The total measurement of rain 

 for the eight months is 932 in., which is 60 per cent, 

 of the average. An examination of the Greenwich 

 observations for the last 105 years shows only one 

 corresponding period as dry, the rainfall for October, 

 1879, to May, 1880, amounting to 824 in., a de- 

 ficiency of 729 in. October, 1873, to May, 1874, had 

 960 in. of rain, and the next driest was apparently 

 October, 1897, ^^ May, 1898, with 1050 in. There 

 have been several spring droughts in the last 100 

 years, and for the four months February to May 

 there have been ten years with the total measurement 

 less than 4 in. This year the measurement for 

 F"ebruary to May was 378 in. The years with the 

 smallest measurements for the corresponding period 

 are 1834 with 260 in., 1857 with 276 in., 1863 with 

 2-90 in., and 1874 with 3- 16 in. Temperature through, 

 out the past eight months was abnormally high, the 

 mean for each month at circenwich being above the 

 average and the excess for the whole period 23°. 



An interesting paper on the cause of quenching 

 cracks in steel was presented at the May meeting 

 of the Iron and Steel Institute by Messrs. Honda, 

 Matsushita, and Idei. The cjiuse is generally believed 

 to be (i) the non-uniform distribution of temperature 

 in the specimen during quenching and (2) the differ- 

 ence in martensitic expansion of adjacent parts during 

 quenching. A closer examination of the phenomena, 

 however, shows that the true cause is not so evident, 

 for the sound due to cracking is often heard some 

 ten seconds after quenching. In small pieces of steel 

 the periphery is harder than the central portion only 

 in a mild quenching ; with a medium quenching the 

 hardness is nearly equal throughout ; while with hard 

 quenching the periphery is always softer than the 

 interior. This anomalous phenomenon is explained 

 by the presence of arrested austenite in martensite. 

 The quenching cracks in small pieces of steel occur 

 when the hardness in the central portion is much 

 greater than in the periphery, and they are attributed 

 to the stress caused by the difference in the specific 

 volumes of austenite and martensite. The specific 

 volume of the former is smaller than that of the 

 latter, and hence the central portion exerts a large 

 tangential tension on the periphery. Since the differ- 

 ence in the specific volumes increases as the tem- 

 perature falls, the cracking usually takes place when 

 the temperature of the quenched specimen approaches 

 that of the room. In a hard quenching the hardness 

 gradually increases with the lapse of time owing to 

 the gradual transformation of the arrested austenite 

 into martensite. 



Mr. a. S. E. Ackermann's first paper dealing with 

 experiments with clay in its relation to piles was the 

 subject of a note in Nature for March 27, 19 19. 

 In his second paper on the same subject — read before 

 the Society of Engineers in October last — the author 

 takes the opportunity of correcting some errors which 

 appeared in the first paper, and points out that 

 further work has confirmed all the previous con- 

 clusions excepting that the effect of temperature on 

 the supporting capacity appears to be limited to 

 stresses below the pressure of fluidity, and that the 

 sides of a hole appear to crush in before the statical 



