March 13, 1919] 



NATURE 



ZZ 



interesting notes on whales landed at the Scottish 

 whaling stations, dealing in the present instalment 

 with the bottle-nose, humpback, and finner whales. 

 During the six \ears covering the period of these 

 observations only twenty of the first-named species 

 ne landed at the Scottish stations, and this, not 

 muse of its rarity, but because it does not pay 

 t-ummercially to take these animals in small numbers, 

 when they have to be towed ashore to be "tried out." 

 Of the specimens landed none were fullv adult. Of 

 the humpback whales only thirty-one specimens were 

 landed in Scotland during this period. Twenty-three 

 were males, the largest of which measured 51 ft. in 

 length. July was the chief month of capture. The 

 finner, or common rorqual, is by far the commonest 

 species taken at these stations, as is shown by the 

 fact that during the period under review no fewer 

 than 2409 were killed. The largest of the females, 

 which slightly exceed the males, measured 81 ft. in 

 length. Finally, in regard to all the species, Prof. 

 Thompson gives some valuable figures as to the rela- 

 tion of the girth to the length, and much verv accept- 

 able information as to migration. 



Mr. C. R.^unkuer {K^. Danske Videnskab. 

 >clskab. Biol. Meddel., i., 3, 1918) contributes a paper 

 iin«French) of considerable detail entitled '" Statistical 

 Investigations on Plant Formations," dealing more 

 . >]>ecially with those of northern Europe. A general 



-cription is given of the frequency and distribution 

 the species entering into the formations, of the 

 I lative proportions of the species, and of the fommon 

 biologic characteristics by which the species of a 

 formation adapt themselves to their habitat. The 

 ( liief points to be noted for a complete ecological 

 (liscription of any given area are summarised, and 

 a scheme is drawn up for a scientific description of 

 plant formations. 



The Department of Agriculture of the Union of 

 Siiuth Africa has issued a useful little pamphlet 

 I Bulletin No. 5, 1918) entitled "Agricultural Grasses 

 and their Culture," by Mr. H. A. Melle. In the early 

 days, when the open veld afforded large areas of excel- 

 lent pasture, little, if any, attention was given to the 

 improvement of pastures. But the smaller farms 

 consequent on a denser population of the country has 

 necessitated experiments with exotic grasses for the 

 improvement of pastures. The pamphlet gives an 

 account of the grasses and some of the forage plants 

 ijirown at the Botanical Experiment Station, Pretoria, 

 and the writer discusses the merits and characteristics 

 <if the different species, so that farmers may judge 

 for themselves which particular grass will be best 

 Miited for their purpose and locality. 



\'oL. VI. of " Fossil Vertebrates in the American 

 -Museum of Natural History" has just been received 

 from the Department of Vertebrate Palaeontology of 

 that institution. It includes contributions 168 to 192, 

 which appeared during the years 1915 to 1917 inclusive, 

 from the studies of Osborn, Matthew, Brown, 

 Granger, Gregory, Mook, Anthony, Watson, and von 

 Huene. These articles are collected from the Museum 

 Bulletin volumes of the corresponding years. The 

 < 'lition is limited to sixty copies, and is distributed to 

 ih<- principal research centres in various countries. 



Mr. R., H. Parsons contributes a valuable paper 

 on the coal consumption of steam-power plant to the 

 Electrical Review of February 21. He points out 

 liiat if the consumption of coal in a power station be 

 plotted against the horse-power developed, all the 

 points lie practically on a straight line. If W be 

 the. number of pounds of coal consumed and P the 

 brake-horse-power developed, then, in symbols, 



NO. 2 5>6, VOL. 103] 



W = a + 6P, where o and b are constants which 

 depend on the plant in the station. Similarly, if W 

 be the number of pounds of steam consumed, we 

 have W' = c + dP, where c and d are constants. These 

 laws are practically identical with the laws which 

 Willans proved in connection with high-speed engines. 

 We deduce, for instance, that the steam consumed 

 per brake-horse-power developed will be W'/P, i.e. 

 d + c/P. It is suggested that the mean lines should 

 be found which give the graphs of W, P and W', P 

 for the central station. If all the actual points shown 

 on the curve lie very near this line, then the station 

 is being worked economically. Whenever the point> 

 lie considerably above the mean line there is neeil 

 for inquiry, and the fault will be found either in the 

 boiler- or in the engine-room. 



.\n article on the economic size of concrete ships 

 appears in Engineering for February 14. The author 

 -Mr. E. O. Williams — plots a series of curves, and 

 deduces from them the following information :— After 

 1500 tons dead-weight the displacement increases more 

 rapidly than the increase in dead-weight. Minimum 

 indicated horse-power per ton dead-weight occurs at 

 8000 tons dead-weight. Minimum cost of hull occurs 

 at 4000 tons dead-weight. From these points it 

 appears that the economic limit to concrete ships is 

 between 5000 and 8000 tons dead-weight. At 

 1500 tons dead-weight the concrete ship is most 

 favourably compared with a steel ship for dis- 

 placement and indicated horse-power. The saving 

 in steel at 1500 tons dead-weight is 74 per cent., and 

 at 8000 tons dead-weight 38 per cent. Vessels 

 above 8000 tons dead-weight are not economic in con- 

 crete; there is no saving in steel at 12,000 tons dead- 

 weight; the displacement and the cost of the hull 

 per ton dead-weight increase rapidly above 8000 tons. 

 Concrete ships are most economical between dead- 

 weights of 1500 and 4000 tons, and the best size is in 

 the neighbourhood of 3500 tons dead-weight. 



The leading article in Engineiering for February 21 

 deals with concrete roads, and considers the requisites 

 of a good road with the view of discussing how far 

 concrete fulfils the requirements. There is no 

 question regarding the hardness of well-made 

 concrete, but the length of life depends upon various 

 other considerations. The road should offer low 

 resistance to the movement of traffic over it. 

 Recently some experiments were made in California 

 with the view of ascertaining the pull necessary on 

 different road surfaces to keep three tons of load in 

 motion after it had been started. With water-bound 

 macadam in good condition the pull was 64 lb. per 

 ton; on a bituminous road, 49 lb.; on unsurfaced 

 concrete, 28 lb. In other words, the load which 

 would be kept in motion by four horses on unsurfaced 

 concrete would require seven horses on an asphaltic 

 surface and nine on a water-bound macadam. Con- 

 crete roads do not disintegrate under the traffic, and 

 do not soften with rain or snow ; ther6 is, therefore, 

 neither dust nor mud. Cleansing the surface can be 

 carried out easily and rapidly without damaging the 

 surface in any way whatever. The surface of a 

 properly made concrete road does not work into waves, 

 nor does it disintegrate or develop holes. The ideal 

 road must not be slippery, and modern concrete roads 

 possess surfaces which afford a good grip for hoof 

 or tyre. Owing to the readiness with which water 

 runs off the surface a much smaller camber may be 

 employed, and there is thus less temptation for dri\'ers 

 to use the middle of the road only. Concrete roads 

 are not affected by climatic conditions. The initial 

 cost is higher, but the maintenance cost is much 

 lower, than both water-bound and bituminous macadam. 



