206 



NA TURE 



\yune 30, 1887 



conditions were almost unknown for Prussia. Some of the 

 stations were inspected yearly by Dove, but strange to 

 say, it is stated that not a single Report of these inspections 

 is to be found in the archives of the Institute. Among 

 the numerous treatises by Prof. Dove, that best known is 

 his woi'k on the '' Law of Storms," which was translated 

 and adopted in this country. After Dove's death, in 1879, 

 the Institute introduced the French measures in its 

 publications, and adopted generally the recommendations 

 of the various International Congresses, to which innova- 

 tions Dove himself had always been averse, and instruments 

 with new scales were necessarily supplied to the stations. 

 In 1882 Dr. Hellmann was intrusted with the ad interim 

 direction of the Institute, and many additional stations, 

 especially for rainfall, were added to those which alreadv 

 existed, and finally (in 1885) the Institute was placed under 

 the able superintendence of Dr. W. von Bezold, formerly 

 director of the Bavarian system, with Drs. Hellmann, 

 Assmann (also Director of the Magdeburg Observatory), 

 Kremser, and Wagner, as principal assistants. The first 

 volume of the new office has just appeared, and contains 

 the observations at 271 stations during the year 1885 

 (246 pages, 4to, and 6 litho. tables), and also lists of all 

 ■observations made since 1847. The stations are still 

 very unequally distributed over the Empire, and no doubt 

 improvements will be made in this respect, from time to 

 time. It is plainly shown from the tables that while an 

 open country position is most suitable meteorologically^ 

 yet for duration of the observations the large towns are 

 preferable. These observations formerly appeared in the 

 •" Preussische Statistik," and in the publication of the 

 Deutsche Seewarte, but will henceforward form an inde- 

 pendent work. It is proposed in future to issue the tabular 

 portion in quarterly volumes, and to publish pamphlets 

 at irregular intervals under the title of " Abtheilungen," 

 containing papers and discussions of a general nature. 

 The Deutsche Seewarte at Hamburg is an independent 

 Institution, dealing chiefly with maritime meteorology 

 and weather telegraphy. J. S. Harding. 



THE HEIGHT OF SUMMER CLOUDS. 



A KNOWLEDGE of the heights and movements of 

 ■^"^ the clouds is of much interest to science, and of 

 especial importance in the prediction of weather ; the 

 subject has therefore I'eceived much attention during 

 recent years from meteorologists, chiefly in this country 

 and in Sweden. In the last published Report of the 

 Meteorological Council for 1885-86 will be found an 

 account of the steps taken by that body to obtain cloud- 

 photographs ; and in the Meteorologische Zeitschrift for 

 March last, MM. Ekholm and Hagstrom have published 

 an interesting summary of the results of observations 

 made at Upsala during the summers of 1884-85. They 

 determined the paraUax of the clouds by angular mea- 

 surements made from two stations at the extremities of 

 a base of convenient length, and having telephonic con- 

 nexion. The instruments used were altazimuths, con- 

 structed under the direction of Prof. Mohn, specially for 

 measuring the parallax of the aurora borealis. A full 

 description of these instruments and of the calculations 

 will be found in the Acta Reg. So:. Sc. Ups. 1884. The 

 results now in question are based upon nearly 1500 

 measurements of heights ; the motions will form the sub- 

 ject of a future paper. It was found that clouds are 

 formed at all levels, but that they occur most frequently 

 at certain elevations or stages. The following are, ap- 

 proximately, the mean heights, in feet, of the principal 

 forms : — Stratus, 2000 ; nimbus, 5000 ; cumulus (base), 

 4500, (summit) 6000 ; cumulo-stratus (base), 4600 ; 

 ^' false-cirrus " (a form which often accompanies the 

 cumulo-stratus), 12,800; cirro-cumulus, 21,000; cirrus, 

 29,000 (the highest being 41,000). The maximum of 



cloud-frequency was found to be at levels of 2300 and 

 5500 feet. Generally speaking, all the forms of cloud 

 have a tendency to rise during the course of the day ; the 

 change, excepting for the cumulus-form, amounting to 

 nearly 6500 feet. In the morning, when the cirrus clouds 

 are at their lowest level, the frequency of their lowest 

 forms — the cirro-cumulus— is greatest ; and in the even- 

 ing, when the height of the cirrus is greatest, the fre- 

 quency of its highest forms— the cirro-stratus — is also 

 greatest. With regard to the connexion between the 

 character of the weather and the height of the clouds, 

 the heights of the bases of the cumulus are nearly con- 

 stant in all conditions. The summits, however, are lowest 

 in the vicinity of a barometric maximum ; they increase 

 in the region of a depression, and attain their greatest 

 height in thunderstorms, the thickness of the cumulo- 

 stratus stretching sometimes for several miles. The highest 

 forms of clouds appear to float at their lowest levels in 

 the region of a depression. The forms of clouds are 

 identical in all parts of the world, as has been shown in 

 papers lately read by the Hon. R. Abercromby before 

 the English and Scottish Meteorological Societies. 



IVAN POLVAKOFF. 



RUSSIA has lost one of her most promising men 

 of science in Ivan Polyakoff, who died lately at 

 St. Petersburg, from hepatic disease, at the age of about 

 fo'.ty. He was born in the small village of Transbaikalia, 

 on the Argun, of Cossack parents, descendants from the 

 earlier settlers of Siberia, and received his first education 

 in a military school for sons of soldiers and Cossacks 

 at Irkutsk — a very limited education indeed. As his 

 parents were poor, and life in his native village offered 

 no attractions, he accepted the position of teacher at the 

 same school where he had been educated. Zoology and 

 botany became the sciences of his choice A large park 

 belonging to the Governor, close by the military school, 

 peopled with a variety of birds and insects, became the 

 first field of his researches. As the spring came, he 

 would spend the day in the garden, sometimes extend- 

 ing his excursions to the neighbourhood of Irkuts'c, 

 where so much is to be learned. He wrote down his 

 observations, and published them in the Irkutsk Gazette. 

 From the very first lines of his description one is struck 

 by a remarkable feature of Polyakoff's mind— a feature 

 which is to be found in all his later writings, and 

 which cannot but be highly appreciated by a true 

 naturalist : it is the simplicity of his conception of the 

 animal world ; I should say his intimacy, his familiarity, 

 with every bird or animal he describes. He understood 

 them. One must be born in a lonely Siberian village on the 

 confines of the civilized world, at the border of the un- 

 inhabited Gobi steppe— the Argun is such a border — to 

 be always in so close a contact with Nature. 



Early in 1866 I was going to make a great journey to 

 find out the long-searched-for route from the Lena gold- 

 washings to the steppes of Transbaikalia. A topographer 

 accompanied the Expedition ; I undertook the geological 

 exploration ; for the botanical and zoological I invited 

 Polyakoft" to join us. We crossed the region from the Lena 

 to Tchita, and thus Polyakoff and I were able to make a 

 section of the backbone of the Asiatic continent, with its 

 high and lower plateaus, their border-ridges, and the 

 Alpine regions which fringe them. A zoologist like 

 Polyakoff was thus enabled to obtain an insight into the 

 whole of the Siberian fauna, as dependent upon orograph- 

 ical features. His descriptions of the fauna and flora 

 of the region, especially with regard to the dependence 

 of animals and plants upon their surroundings and their 

 mutual interdependence — he excelled in that kind of 

 research — are a most valuable contribution to the geo- 

 graphical zoology and botany of a wide region. His 



