August 28, 19 13] 



NATURE 



675 



gratulated on having obtained the help of such an 

 eminent European student as Prof. Bezzi, of Turin. 



The Imperial Bureau of Entomology begins this 

 year to supplement the Bulletin of Entomological 

 Research by a Review of Applied Entomology, issued 

 in two series — A, Agricultural, and B, Medical and 

 Veterinary. Containing records of recent literature, 

 with full summaries, these publications cannot fail 

 to be valuable to students of insect life. 



G. H. C. 



METEOROLOGICAL REPORTS. 

 \/\/E have received the meteorological observations 

 * * made at the Hamburg Astronomical Observatory 

 for 1910-12. This institution was established in the 

 town of Hamburg- in 1825, and was for many years 

 under the able superintendence of Dr. Riimker; it is 

 now situated at Bergedorf, 19 km. E.S.E. of its former 

 position, and is under the superintendence of Dr. 

 Schorr. Very complete and careful observations are 

 made five times daily ; the amount of cloud is also 

 given for each hour between 6h. p.m. and 6h. a.m. 

 The sunshine is recorded by Campbell-Stokes (burn- 

 ing) and Jordan (photographic) instruments. The 

 average annual difference in the possible percentage 

 for 1910-12 is 67 in favour of the Jordan recorder. 

 Although the observations are not strictly comparable, 

 we should not have expected so much difference. An 

 interesting comparison of temperature and humidity 

 in English and French screens is made with the read- 

 ings of an Assmann's aspiration psychrometer. The 

 hourly means of temperature in both screens are 

 generally higher than those of the psychrometer; the 

 greatest differences occur in daytime, especially in 

 the French screen (open at bottom), but at the 9(1. 

 p.m. observation the reverse obtains. Humidity in 

 the screens is generally higher than the readings of 

 tin- psvehrometer, especially during summer. 



The report of the Sonnblick Society for the year 

 19 1 2 contains the results of the meteorological observa- 

 tions on the summit of the Sonnblick, Salzburg 

 (3105 metres), for twenty-five years, 1887-1911, pre- 

 pared bv Hofrat Dr. J. v. Harm. The mean monthly- 

 temperatures were: — January, —13-3° C. (February, 

 — 14-0°); July, 0-9°; year, —6-6°; mean of absolute 

 extremes, 9-5° — 29-7°. Mean yearly precipitation, 

 1715 mm., on 216-7 days. Fog was observed on 251-5 

 days. The mean yearly sunshine was 14969 hours, 

 being 35 per cent, of the possible amount. The dura- 

 tion of sunshine varies greatly in different years ; 

 September. 1895, had 241 hours, August, 1896, only 

 eighteen hours ! November and January have rela- 

 tively the most sunshine. May and June the least. 

 Winter and late autumn are the brightest seasons, 

 April to June the dullest months. Among other use- 

 ful summaries contained in the report we may mention 

 the observations at the summit of the Donnersberg, 

 Bohemia (835 metres), for the years 1905-9. The 

 observatory is attached to the German University at 

 Prague, under the direction of Prof. R. Spitaler. 



The report and meteorological observations at the 

 Roval Observatory. Hong Knng, for the year 1912 

 have reached us; the results have been carefully pre- 

 pared by Mr. T. F. Claxton, formerly director of the 

 Mauritius Observatorv. The tables include hourly 

 values of the principal elements, five-dav means, and 

 results of magnetic observations. The mean annual 

 air-temperature, 71-9°, was about normal; maximum, 

 02-5°, in September; minimum, 45-1°, in December. 

 The rainfall, 63-9 in., was about 20-5 in. below the 

 average. The colony was not actually visited bv a 

 typhoon, but the tracks of those and of the more im- 

 portant depressions which occurred in the Far East 



NO. 2287, VOL. qi] 



during the year are shown on two plates. A weather 

 map and reports from about forty stations are issued 

 daily; the forecasts drawn from these data for various 

 districts show a very high percentage of success. A 

 large amount of data is extracted from ships' logs; 

 this is utilised in determining typhoon tracks, and to 

 some extent for the eventual publication of pilot 

 charts of the Pacific for the area 9 S. to 45 N. 

 latitude, and ioo° to 180 E. longitude, divided into 

 two-degree squares. 



HORTICULTURAL IMESTIGATIONS AT 

 THE WOBURN EXPERIMENTAL FRUIT 

 FARM. 1 



IN a flower, such as that of an apple-tree, 

 there is a tubular structure in the centre, 

 forming the female portion of the flower, and that 

 is surrounded and overtopped by a number of rods, 

 bearing at their extremities sacs of pollen, this con- 

 stituting the male element. When a grain ol pollen, 

 either of the same or another flower, enters the 

 central tube, or pistil, fertilisation occurs, and a seed, 

 or pip, begins to form near the base of the pistil. 

 As it develops, the woody substance surrounding it, 

 which is really a portion of the stalk of the tree, 

 gradually swells to a remarkable extent, and even- 

 tually forms the fleshy or edible portion of the fruit. 

 We commonly call it the fruit, but it is only a meta- 

 morphosed portion of the mother-tree : the real fruit 

 of the tree, the progeny of male and female elements, 

 is the pip. When this is sown in the ground, it 

 germinates, and eventually forms a new tree, which, 

 though probably showing some resemblance to its two 

 parents, will be a new variety, and will not bear 

 apples of the same sort as the mother-tree. On.: 

 reason which makes it all the more improbable that 

 a pip will give rise to a tree bearing fruit like that 

 of the mother-tree, is that in many cases the female 

 portion of the flower cannot be fertilised except by 

 pollen from a tree of a different variety. 



As it is impossible to reproduce a fruit-tree of any 

 given variety from seed, other methods of multiplica- 

 tion must be adopted, namely budding or grafting. 

 A young tree of a similar character is taken (the 

 slock), and in the one case a bud, or in the other case 

 a twig (scion), from the tree to be propagated is united 

 with the stem of the stock. All the growth arising 

 from this bud, or buds, is similar to that of the tree 

 from which it was taken ; the stock acts as little ejse 

 than a channel for conveying nourishment to the in- 

 grafted buds ; yet it does exert a certain influence on 

 the character of the growth of scion. For apples we 

 use two classes of stocks; the one, the crab stock, 

 is obtained bv sowing the seeds of crab-apples, and is 

 characterised by forming a scanty number of roots, 

 but these are stout, and have a tendency to obtain 

 deep hold of the ground; the other, the paradise 

 stock, is derived from a French variety of apple, and 

 forms a much larger number of roots, but smaller, 

 and tending to spread out near the surface of the 

 ground. The grafted tree partakes of the character 

 of the roots of the stock; on the paradise stock it 

 becomes more spreading in its habit, and grows less 

 vigorously than on the crab stock, and, whilst the 

 former is more suitable for growing trees in the bush 

 form, the crab stock is more suited for standard trees. 



In the case of pears, the corresponding stocks are : 

 the pear stock for standard trees, and the quince stock 

 for bush trees. 



It must be remembered, however, that the effect of 

 the stock on the growth of a tree is a subsidiary 



1 From a discourse delivered at the Roval Institution on Friday, 

 February 21, by Mr. Spencer U. Pickering, F.R.S. 



