RESULTS OF COMPARATIVE OBSERVATIONS: PRUSSIA. 251 



soil, and some sinking deeper finally reaches an impervious layer, and 

 again reappears in springs. Even in the heaviest rains, the water eutcis 

 the soil at first but a few centimeters in depth, and after the capillary 

 spaces in the upper strata are filled, the water is absorbed deeper, and by 

 hydrostatic pressure is carried to greater depths. In cultivated soil 

 where there is water in the ground, it is brought to the surface by capil- 

 lary attraction. The chemical and physical condition of the soil and 

 the kind of covering, has a great influence ui)on the amount of rains 

 absorbed, and of water evaporated, and these must change considerably 

 according to the seasons. IShort, heavy falls of rain, especially on 

 slopes, are found to give less water to the soil than those that are gen- 

 tle and protracted, even if the latter furnish actually less water, but 

 interrupted showers wet the ground less than continuous ones, even if 

 of greater amount, from the evaporation that takes place between 

 them. 



Effect of icoodlands vpon Ozone. 



Observations were made to determine the effect of forests upon the 

 amount of ozone in the air, the result of which showed that there was 

 more in the country than in the cities, more in fields near the border of 

 woodlands than within their shade, and more at the level of the tree- 

 tops than near the ground. It was most perceptible in winter, next in 

 spring, less in autumn, and least in summer. No difference was observed 

 by Dr. Ebermayer between evergreen and deciduous forests, but M. Fan- 

 trat, in France, found the amount of ozone somewhat less under resinous 

 woods than under deciduons forests. The latter observer agrees, how- 

 ever, in the statement that there is less within than on the borders of a 

 forest. According to the records made at the Bavarian stations, ozone 

 is more perceptible at higher than at lower elevations, and was least ap- 

 parent in the open country at a distance from forests.^ 



PRUSSIA. 



Forest-meteorological stations were established in Prussia and in 

 Alsace Lorraine in April, 1874, and the system, consisting of seven sta- 

 tions inthe former and three in the latter, is now complete.^ Since January, 

 1875, observations have been published regularly every month, and the 

 annual report for 1875 has appeared.^ The observations are made as in 



'The liite Dr. Charles Smallwood, of Montreal, well known from his careful meteoro- 

 logical stndies, remarked concerning ozone, that " there is no condition of the atmos- 

 phere appreciable by our instruments that indicates the presence of ozone except the 

 prtsence of vapor or humidity " It follows that any cause capable of increasing the 

 relative amount of vapor in the atmosphere tends to the development of this sub- 

 stance. — (On Ozove, and on the Meteorology of the Vicinity of Montreal, li:;57, p. 8.) 



The records of B6rigny, of Versailles, show the influence of the vicinity of forests nnd 

 other A'egetation on the amount of ozone. The maximum is in May, when vegetation 

 is active, and the minimum in November, when the decomposition of the dead haves 

 and plants is the greatest. — (Fox on Ozone and Jntozone, p. 100.) 



Individuals are sent to the pine forests of Prussia and other countries in order that they 

 may breathe the highly ozonized exhalations of the coniferse. The leueficent effects 

 of such a residence in pulmonary affections may, i)erhaps, bo due to some extent, to the 

 direct influence of the turpentine dift^used through the air.— (/&., 113.) 



2 Three new stations were to be established in 1876-'77. In the selection of places, 

 care was taken that the soil, aspect, and general character of surface, and in the wood- 

 laud stations the timber-growths as to age and kind, should be as nearly alike as pos- 

 sible. 



^ Jahrsbericht iiber die Beohachtungs-Ergehnisse der im Eonigreich Prenssen und in den 

 Eeichslanden eingerichteien fdrstlich-meteorologischen Stationen. Berlin, 1877, pp. 91. The 

 report for 1676 has not come to our notice, and we do not know that it has been pub- 

 lished. 



