July 6, 191 6] 



NATURE 



1^1 



Finding that the galvanised tanks commonly used 

 suffered much from the rough handling to which they 

 were subjected on shipboard, wooden tanks were 

 substituted. These have a capacity of 156 gallons, 

 and have proved in every way preferable. A great 

 saving both of labour and expense has been effected 

 by feeding the fish on alternate days instead of every 

 day. The mortality has also decreased, an excess of 

 fat having resulted from a too liberal diet. Altogether 

 more than 3000 fishes, representing 140 species, are 

 exhibited here, and among these are an unusually 

 fine series of tropical species, and "jew-fishes" up to 

 500 lb. in weight. The porpoises died during the year 

 from water fouled by sewage ; to avoid losses from 

 this source filtering tanks have been established, 

 with eminently satisfactory results. 



In Californian Fish and Game, the journal pub- 

 lished by the Board of Fish and Game Commissioners 

 of San Francisco, vol. ii.. No. 2, Mr. Chase Little- 

 john gives a brief but valuable account of the habits 

 and hunting of the sea-otter, which is fast nearing 

 extinction. As the author was himself for some years 

 engaged in hunting this animal, his summary makes 

 an important addition to our knowledge of its life- 

 history. Unlike all other aquatic mammals, the sea- 

 otter, he tells us, swims on its back, turning swiftly 

 over when about to dive, but he affords no informa- 

 tion as to the part played by the tail while swimming 

 at the surface. Sea-urchins appear to be the staple 

 food of this animal, and these are brought to the 

 surface and eaten as the swimmer floats upon his 

 back. Squids and seaweed are also eaten, and 

 occasionally fish. After man, the greatest enemy 

 of the sea-otter is the killer-whale, from which it 

 contrives, at times, to escape by floating at the surface 

 as if dead. In the early days of the author's hunting, 

 sea-otters were met with off the coasts of Japan 

 in "schools" of as many as 400, but owing to the 

 merciless persecution to which they have been sub- 

 jected hunting is now no longer a profitable under- 

 taking and has been abandoned. 



British Birds for June contains the first of what 

 promises to be a valuable series of records on the 

 breeding habits of the sparrow-hawk. In the present 

 contribution the author, Mr. J. H. Owen, describes ^he 

 behaviour of the adults towards the young during rain. 

 Ordinarily, after the young are a few days old, the hen 

 does not require her mate to bring food to the nest. 

 In rain, and especially in heavy rain, this is not so. 

 She takes no notice of his calls, and he has to bring 

 the food and deposit it on the nest. If the rain is 

 not very heavy she will then break it up and dis- 

 tribute it, but in a heavy downpour she will wait 

 until its violence has ceased rather than expose her 

 offspring to the danger of a soaking. During pelting 

 rain the hen, hurrying home at the first sign of 

 the impending storm, stands over her young with 

 outspread wings, taking especial care to cover her 

 youngest completely. When the storm ceases she 

 will take up her position on some neighbouring tree 

 and expose her sodden plumage to the sun and air. 

 The down of the nestlings seems never to get 

 thoroughly soaked, and no attempt is made to preen 

 it until some time after the hen has left them. This 

 account is illustrated by some excellent photographs. 



In the Journal of the Royal Horticultural Society 

 (vol. xli., part 3, for May) Mr. C. H. Senn contributes 

 a useful paper on leaf vegetables and how to cook 

 them. Vegetables are essential to both good eating and 

 good health, so that their proper preparation and 

 cooking are matters of the first importance. Compared 

 with other articles of diet — fish, meat, and poultry — 



NO. 2436, VOL. 97] 



vegetables when properly cooked can be converted 

 into correctly balanced food at about one-third the 

 cost. The importance of paying attention to such 

 matters is therefore essential, especially at the present 

 time. 



The importance of the Canary Island palm. Phoenix 

 canariensis , is referred to in Kew' Bulletin No. a. 

 Dr. G. V. Perez states that it is the best wind-break 

 for plantations and also that it is an ideal tree to 

 plant along river-banks to prevent soil erosion. In 

 addition, the hard kernels are found in the Canaries 

 to be one of the best and most fattening foods for 

 pigs, and they are also relished by goats. Dr. Perez 

 mentions that he is feeding a milch-cow on the kernels 

 after steeping them for a few days in water, and has 

 found them useful for fattening turkeys. Palm honey 

 can be obtained from the trees by tapping. The prac- 

 tice of tapping the palms was probably introduced from 

 the opposite coast of Africa by the aborigines of the 

 islands. 



In vol. Ixxvi. of the Journal of the Royal Agri- 

 cultural Society, recently issued. Dr. Winifred Brench- 

 ley describes the weeds on arable land and the best 

 means for their suppression. Surveys of considerable 

 areas of agricultural England have shown that com- 

 paratively few weeds are definitely associated with a 

 single type of soil. Some of the most noxious weeds, 

 from the farmer's point of view, are quite indifferent 

 to soil variations ; others, although of general dis- 

 tribution, are more frequently found on certain soils; 

 while a small number are characteristic of particular 

 soils, more especially sand and chalk. The methods 

 of suppression applicable to annual and perennial 

 weeds are dealt with generally, special treatments 

 being prescribed for the most noxious species. Thus 

 charlock {Brassica arvensis) is very susceptible to 

 sprays of copper and iron sulphates, which do no 

 harm to cereals growing in the same field, as their 

 long, narrow leaves do not hold the poisons like the 

 rough leaves of the weed. In this connection it may 

 be noted that arsenical sprays have been used success- 

 fully abroad for weed eradication on a large scale. 

 Sometimes a weed becomes so firmly established that 

 ordinar>' methods are useless, and fallowing or a 

 change in the rotation must be tried. .\s jbl rule, 

 thorough cultivation of the soil at the right times — 

 and it is here that Dr. Brenchley's paper will greatly 

 help the farmer — is all that is required. 



Some notes on the meteorological obser\ations of 

 Roald Amundsen's .'\ntarctic expedition of 1911-12 

 appear in Naturen, a monthly publication of the 

 Bergen Museum, for March and April, 1916 (vol. xl., 

 Nos. 3 and 4). The paper is by H. Mohn, who was 

 responsible for the volume on meteorology in the 

 scientific publications of the expedition. Prof. Mohn 

 points out that the observations support the idea, 

 advocated by Prof. Meinardus, that there is a cyclonic 

 movement of air over the -\ntarctic plateau. The 

 winds seem to have a comparatively high temperature 

 and the characteristics of cyclonic winds. The pres- 

 sure observations showed a decrease towards the Pole. 

 The existence of cyclonic conditions over the continent 

 \\x)uld account for the heavy snowfall that must have 

 been required for the formation of the ice-cap. On 

 the other hand, it must be remembered that there are 

 evidences that the snowfall in Antarctica is less than 

 it was and insufficient to account for the formation 

 of the ice. Certainly it is not proved that the inferior 

 snowfall on the plateau is heavj-, and it must not be 

 forgotten that we have no winter observations, except 

 on the coast. 



