828 



NATURE 



[August 25, 192 1 



Old Red Sandstone and Silurian country of Southern 

 Ireland. 



From Australasia we receive comprehensive de- 

 scriptions of the "Palaeozoic Geology of Victoria," by 

 E. O. Teale (Proc. Roy. Soc. Victoria, vol. xxxii., 

 p. 67), with a map of the" Mount Wellington area ; also 

 of the "Geology of Western Australia," bv A. Gibb 

 Maitland, extracted from the Mining Handbook pub- 

 lished in 19 19 by the Geological Survey. The latter 

 memoir has excellent sketch-maps and illustrations 

 throughout the text, and includes a large coloured 

 geological map of the State, dated 1920, corresponding 

 with that described in Nature, vol. cv., p. 498. This 

 summary should be serviceable in very many 

 libraries in the homeland, and should be made avail- 

 able in all Australian schools. 



In Bulletin 21, at the moderate price of 55., the 

 New Zealand Geological Survey continues its illus- 

 trated descriptions of the Dominion. The Osborne 

 and Whatatutu subdivisions, which are here dealt 

 with by J. Henderson and M. Ongley, lie on the 

 east side of North Island, and include peaks rising 

 to 4000 ft. on the main divide. Oil is found in the 

 ■district, probably oozing from the Te Aral (Lower 

 Miocene) and Cretaceous strata. As usual in these 

 bulletins, the authors pay full attention to the origin 

 of surface-features, and one of thqjr pleasing land- 

 scapes shows us, incidentally, the gathering of 

 thousands of sheep under the raised rock-platform 

 of Waihau Beach. 



New Zealand now extends its responsibilities to 

 Pacific isles; and J. Allan Thomson describes (iV.Z. 



Journal of Sciettce and Technology, vol. iv., p. 49, 

 192 1) the geology of W^estern Samoa. The lava- 

 tunnels appear to have been used as dwellings, and 

 terraces for sleeping-accommodation have been built 

 up in them— a feature that will pleasantly remind 

 playgoers of the opening scene of Kelly's "Bird of 

 Paradise." 



Among .American publications, we may note, for 

 comparison with the Triassic beds of Cheshire, the 

 cemented sand-dunes of Eocene age in north-eastern 

 Montana (A. J. Collier, U.S. Geol. Surv., Prof. 

 Paper 120-B, plate iv.), and the cross-bedded De 

 Chelly sandstones (Permian?) of Arizona (H. E. 

 Gregory, ibid., Prof. Paper 93, p. 31, etc.). The 

 latter paper, which is on the " Geology of the Navajo 

 Country," contains notable illustrations of erosion in 

 an arid land. E. G. Fenton (Sci. Proc. Royal 

 Dublin Soc., vol. xvi.. No. 19, 192 1, 45. 6d.), 

 in his "Studies in the Physiography £"nd Glacial 

 Geology of Southern Patagonia," brings us to an un- 

 usual field. He has specially examined, through 

 years of residence, the results of glacial outwash and 

 of river-erosion between the .Andes and the Atlantic 

 coast. He interestingly attributes the hollows known 

 as bajos to the action of water falling over an ice- 

 front during a pause in the general retreat of the 

 pampas glaciers. Though he traces several epochs 

 of retreat and of renewed glaciation, during some of 

 which lavas flowed down into valleys cut by rivers 

 streaming from the ice. Dr. Fenton finds no evidence 

 of anv genial interglacial epoch in Patagonia. 



G. A. J. C. 



Artificial Farmyard Manure. 



AN article in the current issue (.\ugust) of the 

 Journal of the Ministry of Agriculture under 

 the above title somewhat modestly announces what 

 must be regarded as one of the most notable advances 

 in agricultural science made by our oldest agricul- 

 tural research laboratory, the Rothamsted Experi- 

 mental Station. For many years the composition and 

 fertilising value of farmyard manure have occupied 

 the attention of investigators. The chemical problems 

 involved at first sight appear simple. When cattle 

 are fed with food rich in nitrogen there is a corre- 

 sptmding enrichment of their excrement. "Cake- 

 fed " dung has long been given a high value by the 

 farmer, and on a purely chemical basis its merit was 

 recognised bv the man of science. Hence such pub- 

 lications as "Hall and Voe'lcker's Tables," which 

 give the "residual" values of various foodstuffs — 

 that is to say, the value of the fertilising constituents 

 (mainly nitrogen) in various substances present in 

 the dung of animals to which they have been fed. 

 But the perplexing fact emerged that dung with this 

 higher theoretic value did not give crop increases 

 corresponding to its assumed chemical content. 

 Nevertheless, so strong has been the effect of the 

 publication of these theoretic values that they are 

 given quasi-statutory effect. Entering tenants have 

 generallv to pay compensation "for improvements" 

 based upon the quantity and quality of the foods con- 

 sumed on the farm during the years preceding their 

 entry. 



In the paper alluded to Messrs. Hutchinson and 

 Richards indicate the solution of the conundrum. 

 Put shortly, they have established that the whole of 

 nitrogen in the urine of animals will not be present 

 in the manure as applied to the crops unless a certain 

 ratio subsists between the nitrogen voided by the 

 ■animals and the carbonaceous matter of the litter by 

 NO. 2704, VOL. 107] 



which the urine is absorbed. It seems to follow that 

 "compensation for improvements" should not be 

 awarded on the basis of the food supplied to the 

 stock until the valuer is assured that the feeding was 

 accompanied by an adequate supply of litter, the 

 adequacy being determined by the amount of nitrogen 

 voided by the animals. 



Messrs. Hutchinson and Richards show that the 

 factors involved are, in the main, biological, not 

 chemical. The "making" of farmyard manure is 

 essentially the rotting or fermentation of straw. The 

 former writer has published a paper (Journal of 

 Agricultural Science, 19 19, p. 143) which estab- 

 lishes that straw is fermented by a new aerobic 

 organism, Spirochaeta cytophaga, and that this 

 organism requires (in addition to air) a supply of 

 nitrogen, preferably in the form of an ammonia 

 compound (such as. In effect, urea is). It is shown 

 that the amount of nitrogen required for the fer- 

 mentation of 100 lb. of straw is 072 lb. Further, if 

 the nitrogen is in excess of this amount, it tends to 

 pass Into the atmosphere as ammonia, with the 

 result that, with a free supply of air, the end product 

 Is dung containing about 2 per cent, of nitrogen, 

 whatever the original content of the excrement may 

 have been. Under the conditions, however, which 

 obtain In the ordinary farmA-ard, where some portions 

 of the heap may receive more excrementitious matter 

 than others, the'ammonia set free where the nitrogen : 

 cellulose proportion is greater than 072 : 100 may 

 be picked up by those portions where the ratio is 

 less, and used to build up their nitrogen content until 

 the whole heap reaches the characteristic and uniform 

 2 per cent, content of nitrogen. 



Using these results. It has been found possible to 

 make an artificial product, closely resembling farm- 

 yard manure In appearance as well as in properties, by 



