April 6, 191 1] 



NATURE 



185 



sum approximating 4000L ; even so, it is impossible 

 to estimate its worth to tlie country, either directly 

 or indirectly ; but the editor thinks the saving effected 

 bv the campaign may be safely set down as at least a 

 hundredfold. As first of all there is the direct benefit 

 which accrues from the saving of the crops, and, 

 second, the destruction of vast armies of locusts, which 

 will materially lessen if not entirely prevent the re- 

 currence of swarms during the succeeding season. 



In comparing the 1909 visitation with that of pre- 

 vious years, it is stated that it was probably the most 

 severe one which has been experienced since 1893, 

 as altogether no fewer than 15,306 swarms were 

 accounted for and tabulated in the monthly returns. 

 These do not, however, take into account the numerous 

 swarms destroyed by the Railway Department or in 

 those districts where there was no locust officer. 



The term swarm is of exceedingly vague significance 

 and it is quite impossible to estimate the average size 

 of those which were destroyed. But these may be 

 said to have varied in size from those covering a few- 

 square rods to others of such magnitude that they 

 covered hundreds of acres. In the initial stages of 

 the 1909 invasion the insects came down in immense 

 swarms from the Kalahari Desert in March, and 

 subsequently mighty swarms swept the country clean 

 to the coast of the Indian Ocean between Port Eliza- 

 '■■th and East London, the females depositing their 

 _;s more or less all the way from the desert to the 

 I, where they covered an area of country about 

 I miles in width. 



The most highly favoured of all the agents used 

 the destruction of locusts is a mixture of arsenite 

 soda and treacle. In preparing this the custom is 

 dissolve 200 lbs. of the arsenite in about 15 gallons 

 l)oiling water and then to add water until the bulk 

 i- 20 gallons. Half a jijallon of this is then poured 

 into an iron drain, specially manufactured for the pur- 

 ])i>s(', and a gallon of the treacle or syrup added; the 

 \\ hole is then thoroughly mixed, the drumhead fixed, 

 ;i!id the material is then ready for transport. The 

 dilution of the poison recommended by the department 

 i-. one part to 66 of water for newly-hatched locusts 

 ( ■ \'oetgangers "), and one part to 50 when the insects 

 ;iiv' about a fortnight old. Mr. C. P. Lounsbury 

 I II lints out, however, that no single means of destruc- 

 tion can be recommended for use in all circum- 

 stances, and that spraying with either the arsenical 

 poison or with a soap solution is applicable only where 

 water is available. The soap emulsions make the 

 cb.eapest spraying solutions for killing the locusts hy 

 contact, but if the solution is too highly diluted with 

 water the insects may be stupefied for a few hours and 

 finally recover. On the other hand, the arsenical pre- 

 paration acts as a stomach poison and kills them- more 

 or less quickly, according to the strength at which it is 

 used. When poison is used it is lightly sprayed around 

 or over the swarms, or in front of them if they are on 

 the move. This preparation has unfortunately a 

 deadly effect upon the vegetation, and cattle should 

 not be allowed to graze upon the sprayed areas until 

 after a good rain, or after the dead herbage has been 

 fired. Whole areas of crops under cultivation must 

 not be sprayed, and in such circumstances poisoned 

 baits may be used with excellent results, and the most 

 marked feature of the recent work of locust de- 

 struction was due to the vastly increased use of such 

 "baits." Various materials are used, but finelv- 

 chopped green forage is claimed to be the best. As 

 a substitute bran, mixed with the poison, is also 

 stronjrlv recommended by the officer in charge of the 

 Caradoc district, but it is thought that this may have 

 a deadly effect upon small birds, and is not generally 

 advocated. 



One of the most interesting- chapters in this report 



NO. 2162, VOL. 86] 



is that which deals with locust-eating birds, the species 

 referred to being the white stork {Ciconia alba), 

 though other members of the pelargi are evidently 

 included, and small pratincoles (Limicolae). It is 

 stated that these birds practically cleared the country 

 of the swarms of locusts that had escaped being 

 poisoned, and that they are the leading factors 

 in the natural control of these pests. This is not the 

 first occasion that the bureau has published informa- 

 tion regarding this destruction of locusts by birds ; 

 it may be recalled here that information was given 

 in the previous report, in which it was stated that 

 the swarms of locusts which occurred in the country 

 bordering;- on the Kalahari were practically exter- 

 minated bv them. 



TOTAL ECLIPSE OF THE SUN, APRIL 2S, 1911. 



ALTHOUGH the eclipse which is due to occur on 

 Friday, April 28, 1911, will only be visible along 

 a narrow track extending from the south-eastern 

 coast of Australia to the islands about Samoa, it has 

 attracted a strong contingent of both official and 

 private observers. In spite of the comparative diffi- 

 culty of access, it was considered that this, being the 

 last of the series of long-duration eclipses for some 

 years to come, warranted a special attempt being 

 made to secure the important observations, spectro- 

 scopic and topographic, which can as yet only be 

 efficiently made during the period of eclipse. 



After very careful consideration of all possible 

 situations, most of the parties have proceeded to a 

 small coral island, Vavau, one of the Friendlv Group in 

 lat. 18° 39' S. ; long. 173° 59' W. Three English 

 parties have arranged to observe the eclipse in the 

 vicinity of Neiafu, the chief town of Vavau. The 

 constitution of these, with their instrumental equip- 

 ment, is as follows : — 



(i) Government Expedition from Solar Physics 

 Observatory. — Dr. W. J. S. Lockyer, in charge of this 

 party, and accompanied by Mr. F. K. McClean, left 

 London on February 3, 191 1, with the necessary gear, 

 and journeyed to Sydney by the Orient s.s. Otway. 

 From there the instruments were transhipped to 

 H.M.S. Encounter, of the Australian Squadron, and 

 the expedition started for the Friendly Islands on 

 March 25. Their equipment consists of :■ — 



(a) 6-inch prismatic camera, 7 feet 6 inches focal length, 

 with four large objective prisms of 45° angle. With this 

 instrument it is hoped to photograph ihe spectrum of the 

 sun's atmosphere at second and third contacts, and also 

 to obtain several records of the coronal spectrum during 

 totality. This will be used in connection with a i2-inch 

 siderostat. 



(b) Concave Rowland Grating Spectrograph, of 10 feet 

 radius of curvature, arranged as a slit spectrograph for the 

 first-order spectrum. A special plate holder has been pro- 

 vided, carrying six celluloid isothromatic films, 24 inches 

 long, bent to the curvature of the focal curve. A Cooke 

 photo-visual triple objective of 30 feet focal length, receiv- 

 ing light from a 21-inch siderostat, will form an image of 

 the sun about 3J inches diameter on the slit plate. An 

 endeavour will be made to photograph the spectrum of the 

 cusps and of the corona during totality. 



(c) Cooke Coronograph, 4 inches aperture and 16 feet 

 focal length. 



(d) De La Rue Coronograph, 4I inches aperture and 

 8 teet focal length. 



(e) Doublet Coronograph, 5 inches aperture and 30 

 inches focal length. 



(/) Doublet, 6 inches aperture and 48 inches focal length. 



Two small spectrographs will also be used with 

 Thorp replica diffraction gratings placed in front of 

 the camera lenses. To feed these instruments with 

 light two siderostats, of 21 inches and 12 inches 

 aperture respectively, and a coelostat of 16 inches 

 aperture, have been taken by the expedition. On 



