io6 



NA TURE 



[May 30, 1 90 1 



these rocks to the other similar materials in the Phle- 

 graean region are next discussed, and the authors then 

 pass to the structure of the island, which they show to 

 consist of successive sheets or banks of ejected frag- 

 mentary volcanic material without any accompanying 

 lavas, and disposed in the usual divergent arrangement, 

 the portions on the outer surface of the cone dipping 

 steeply outwards into the sea, while those on the inside 

 are inclined towards the centre of the crater. \'ivara 

 rises out of the Mediterranean as a truncated cone which 

 attains a height of 109 metres and a diameter across its 

 upper rim of about 900 metres. The eastern half of the 

 cone has been broken down and the sea now fills the 

 circular crater. The waves and rains have cut many 

 sections of the rocks, and thus the structure of the old 

 volcano has been admirably dissected. All students of 

 vulcanology will welcome these memoirs and hope that 

 they may be regarded as the precursors of a long series 

 in which the volcanic history of Southern Italy will be 

 thoroughly elucidated. Arch. Geikie, 



AGRICULTURE IN NEW SOUTH WALES. 



"^UY. Agricultural Gazctle o{ New South Wales has 

 -*- ushered in the century, and, at the same time, 

 marked the consummation of an Australian Common- 

 wealth, by issuing a special federal edition. The history 

 of the agricultural development of the Colony is dealt 

 withrin most interesting fashion by the chief inspector of 

 agriculture, Mr. W. S. Campbell, who, in the hundred 

 and thirteen pages that he appropriates, unfolds a 

 fascinating tale of the early struggles and final success of 

 this ofifspring of Great Britain, whose birth dates from 

 the year 178S. 



In the section devoted to chemistry in relation to agri- 

 culture a considerable feature is made of the value to the 

 agriculturist of soil-analysis. Expert advice in the treat- 

 ment of soils is said to be much sought after by the farmers 

 of New South Wales, and a typical report on a poor soil 

 is inserted with the view of showing the form that the 

 information takes. The results of the physical and 

 chemical tests are first tabulated, and from these the soil 

 specialist formulates the following recommendations ; — 

 ■" This is a very sour soil, low in plant-food, and only 

 moderately supplied with humus. Its retentive power for 

 water is low, consec|uently its power of resisting drought. 

 It will not give the best results till sweetened and brought 

 into good condition. The treatment recommended is, 

 first, liming at the rate of about one ton per acre. This 

 will sweeten the soil, and supply lime in which the soil is 

 deficient. Then a quick-growing crop, such as vetches, 

 lupins, cow-pea, &c., should be grown and ploughed 

 under when just maturing. This will supply vegetable 

 matter, improve the texture, and supply nitrogen, in all 

 of which essentials the soil is weak. After this treatment 

 the soil should be able, with proper manuring, to grow 

 any of the ordinary fruits suitable to the district, such as 

 are mentioned in your letter. Peaches and stone fruit 

 should do very well, as well as any vegetables. With 

 regard to the most suitable manuring, this should be on 

 the lines recommended in the attached departmental 

 pamphlet, ' Formuht- for Fertilisers,' which gives the 

 manuring required for the different crops in average soil. 

 In your case the quantities recommended may be some- 

 what increased. I would particularly impress upon you, 

 (i) That this report is intended to be merely suggestive, 

 and must be followed up by careful experiments on your 

 own part ; (2) . . . . (3) That you should impart to your 

 neighbours any information you may gain from this 

 report as freely as it is given to you ; (4) That you should 

 communicate regularly with the Department as to the 

 results of your experiments, for we have special facilities 

 for advising you as to the best manures for your special 



NO. 1648, VOL. 64] 



needs, and the cheapest form in which you can get the 

 same." 



This typical report is reprinted almost in full in order 

 to show what the Department of Agriculture of New 

 South Wales professes to be able to do in one section of 

 the farmer's business, namely, the management of his soil. 

 Experience in other countries has shown that advice 

 given in the light of laboratory tests on soil is apt to 

 be rather uncertain in its results, but in Australia science 

 has, in this respect, it is said, been very useful to farmers. 

 The practice of liming in that country seems to vary con- 

 siderably from what holds in England. Where sourness 

 in soil is the trouble an English farmer would consider 

 a dressing of five tons of lime per acre none too much, 

 but in New South Wales one ton is recommended as the 

 maximum dose, to be repeated, if need be, a few years 

 later. 



Not the least interesting section of this federal number 

 is that which treats of agricultural education. Technical 

 instruction in agriculture appears to be eminently practical, 

 and it is noted with satisfaction " that among the large 

 number of young people so trained there are to be found 

 so great a proportion who have achieved signal success 

 upon farms and orchards of their own." The curriculum 

 at the Hawkesbury College is almost rigorous in its 

 thoroughness. The students who are on dairy duty turn 

 out at 4.15 a.m., and are probably ready for their break- 

 fast, which is served at seven. The sixty-five horses and 

 mules that cultivate the College farm of 1 100 acres 

 demand the attention of another " gang " of students, 

 whose day's work does not close till 8 p.m. Hard manual 

 work does not appear to discourage the young farmer of 

 New South Wales in his pursuit of knowledge, the 

 present accommodation of the College being inadequate 

 to meet the demands for admission. Some illustrations 

 of the practical character of the education are culled from 

 the interesting volume before us, which reflects a colonial 

 vitality most gratifying to the mother-country. 



CLIMATE AND TIME AND MARS. 



THE astronomical theory of an Ice Age, of which the 

 foundation is attributed to Adhemar, has been the 

 subject of much discussion. Its laborious exposition by 

 Dr. CroU has been justly considered a work of great 

 merit, but it may be said to have proved more interesting 

 as a speculation than convincing as an argument. The 

 adequacy of the theory to explain all that is required of 

 it is a highly controversial matter, and was debated with 

 no little heat in the columns of this journal in 1895-6. 

 Consequently it is desirable to state that this note is 

 written from the point of view of qualified belief in the 

 argument as expounded by Sir R. Ball. 



The contribution of astronomy to the data of the pro- 

 blem can be very easily stated. Let us consider the 

 northern hemisphere of a planet, the eccentricity of whose 

 orbit, i', is sensible, but so small that only its first power 

 need be taken into account. In the first place the ratio 

 of the total solar radiation received in summer and winter 

 \s \+a:i-a, where ,i = 2 sin w V, w being the obliquity 

 of the equator to the orbit. This is the law discovered 

 by Wiener, and in the case of the earth a = -25. The 

 ratio of the duration of summer and winter, i.c . of the 

 periods between the equinoxes, is \+b:\-b, where 

 b =4t--sinX TT, \ being the true anomaly of the spring 

 equinox. Hence the ratio of the mean heat received in 

 a given time in summer and winter is (H-«)/(i-l-^) : 

 (i -«)/(! -/)). In the southern hemisphere the corre- 

 sponding ratio is (i -l-rt)/(i - *) : (i -iz);'(H-'''). At the 

 present time /' = '02, but in circumstances which would 

 cause the earth's eccentricity to reach its maximum 

 value (about '0747), b = -09 when X = 90'. Under such 

 conditions, then, the southern winter would un- 



