June 6, 19191 



SCIENCE 



537 



cipal rivers, capitals and the largest cities in 

 the different states are also embodied. 



The map is of special interest from the fact 

 that it is based on the same system of projec- 

 tion as that employed by the armies of the 

 allied forces in the military operations in 

 France. To meet those requirements and at 

 the request of the army, special publications 

 were prepared by the Coast and Geodetic Sur- 

 vey. 



Many methods of projection have been de- 

 signed to solve the difficult problem of repre- 

 senting a spherical surface on a plane. As dif- 

 ferent projections have unquestionable merits 

 as well as equally serious* defects, the an- 

 nouncement states, any region to be mapped 

 should be made the subject of special study 

 and that system of projection adopted which 

 will give the best results for the area under 

 consideration. 



The Mercator projection, almost universally 

 used for nautical charts, is responsible for 

 many false impressions of the relative size of 

 the countries differing in laititude, according 

 to the survey statement. The polyconic pro- 

 jection, widely used and well adapted for both 

 topographic and hydrographic surveys, when 

 used for the whole of the United States in one 

 map has the serious defect of unduly exag- 

 gerating the areas on its eastern and western 

 limits. Along the Pacific coast and in Maine 

 the error in scale is as much as 6i per cent., 

 while at New York it reaches 4i per cent. 



The value of the new outline map on the 

 Lambert projection can best be realized when 

 it is stated that it shows that throughout the 

 largest and most important part of the United 

 States, that is, between latitude 30J degrees 

 and 49 degrees, the maximum scale error is 

 only one half of 1 per cent. This amount of 

 scale error of one half of 1 per cent, is fre- 

 quently less than the distortion due to the 

 method of printing and to changes from the 

 humidity of the air. Only in southernmost 

 Florida and Texas does this projection attain 

 its maximum error of 2 1-3 per cent. 



The Lambert projection is well adapted to 

 large areas of predominating east and west di- . 

 mensions in the United States where the dis- 



tance across from east to west is 14.5 times 

 that of the distance north and south. 



The strength of the Polyconic projection, on 

 the other hand, is along its central meridian. 

 The merits and defects of the two systems of 

 projection may be stated in a general way as 

 being at right angles to each other. 



Special features of the Lambert projection 

 that are not found in the Polyconic may be 

 stated briefly as follows: 



1. The Lambert projection is conformal — 

 that is, all angles between intersecting lines or 

 curves are preserved, and for any given point 

 (or restricted locality) the ratio of the length 

 of a linear element on the earth's surface to 

 the length of the corresponding map element 

 is constant for all azimuths or directions in 

 which the element may be taken. 



2. The meridians are straight lines, and the 

 parallels are concentric circles. 



3. It has two axes of strength instead of one, 

 the standard parallels of the map of the United 

 States being latitudes 33 degrees and 45 de- 

 grees, and upon these parallels the scale is ab- 

 solutely true. The scale for any other part of 

 the map, or for any parallel, can be obtained 

 from special publication number 52, page 36, 

 U. S. Coast and Geodetic Survey. By means 

 of these tables the very small scale errors which 

 exist in this projection can be entirely elimi- 

 nated. 



The map measures 25 inches by 39 inches 

 and will be sold by the government at 25 cents. 



THE LECONTE MEMORIAL LECTIJRE IN THB 

 YOSEMITE, 1919 



The University of California through its 

 university extension division will offer free to 

 the public a course of scientific lectures in the 

 Yosemite Valley during June and July. 1919. 

 Those are to be known as the LeConte Memo- 

 rial Lectures in the Yosemite in honor of the 

 name of Joseph LeConte, the famous natural- 

 ist and geologist who was for many years a 

 member of the faculty of the University of 

 California. The lecturers and topics for 1919 

 and the tentative dates are as follows : 



I. Professor W. L. Jepson, department of 

 botany. University of California. 

 1. The Origin and Distribution of But- 



