Periodical Literature. 299 



As a basis for management the logging units, the species, the 

 age of the stands, the site quality, and the density are all set forth 

 on the best forest maps. Three methods of representing this data 

 may be employed namely: Color for species and tones for age; 

 color for species and hatching for age; symbols for species and 

 colors for age. 



The latter method is considered best by the author. An elabo- 

 rate set of symbols are given for differentiating the different 

 species. Non-productive soil is indicated by an absence of color- 

 ing. Age is shown by varying the tones of the basic color. Site 

 quality is indicated by roman numerals and density by arable 

 numerals. The cutting areas are shown by hatching and the 

 working sections are bounded by a special form of border. 



In order to make sure that maps will last for ten or twenty years 

 they should be mounted on linen or prepared on a special form of 

 paper into which linen threads are compressed. For ease of re- 

 production the base map of which an indefinite number of copies 

 can be readily made should contain all permanent features such 

 as topography, roads, and ownership lines. Then it is only neces- 

 sary to add by hand work the coloring and symbols which indicate 

 the more ephemeral characters. 



Die Herstellung forstUcher Bestandsubersichts-und IVirtschaftskartcn. 

 Forstwissenschaftliches Centralblatt. January, 1912, pp. 10-27. 



Oberforster Fischer develops in a very neat 

 Approximating and easy manner the possibiUty of solving 

 Compound compound interest calculations without in- 



Inferest. terest tables or logarithms, quickly and suf- 



ficiently approximately for the purpose of 

 gaining an insight into financial relations. 



He starts by showing that capital doubles, i. e. i.op"=:2. if np 

 (or 100 log 2) =70 approximately. E. g. 

 with 2 per cent, capital doubles in 70 : 2=35 years 

 with 2.5 per cent capital doubles in 70 : 2.5=28 years 

 with 3 per cent, capital doubles in 70 : 3=23.5 years 

 Again to treble, quadruple, etc., the capital, i. e. 



19 



