TWENTY-FIRST ANNUAL REPORT 109 



of building's along the Southern Boulevard were made for the 

 Park engineer, Mr. Beerbower. 



The complete elimination of certain coal-tar derivatives 

 brought from Germany has caused a great advance in the prices 

 of the essential photographic chemicals. Figures compiled by 

 the Motion Picture World, the organ of the motion picture pro- 

 ducers, are almost beyond belief. Metol, one of the most neces- 

 sary chemicals used in developers for the production of nega- 

 tives leaped from $4.50 per pound to $75.00 and $100.00 ; hydro- 

 quinone from 9<) cents to $9.00 per pound; oxalic acid from 10 

 cents to $5.00. Some of the potashes have advanced 300 per 

 cent., and aniline dyes 500 per cent. 



Printing papers have increased from 15 to 20 per cent. ; 

 and dry plates, because of the scarcity of Belgian glass, which 

 is used ahnost exclusively, have advanced 25 per cent. 



American manufacturers are now producing, in limited 

 quantities, substitutes for many of the German products. The 

 radical changes that have become necessary in the manufac- 

 ture of photographic products have produced correspondingly 

 bad effects, and salesmen of one of the large manufactures stated 

 that in all the years of their business career there were never 

 so many difficulties with plates and paper as have been apparent 

 in the last two years. It is to be expected, however, that within 

 a few months all these difficulties will be smoothed away, and 

 the production of photographic supplies will firmly settle down 

 upon an ail-American basis. 



Bulletin. — Six numbers of the Zoological Society Bulletin 

 were issued in 1916. Several numbers contained very valuable 

 and interesting material, furnished by Mr. Beebe from the Trop- 

 ical Research Station, and Mr. Ditmars from his expedition to 

 the low-lands of the Savannah River. Continued progress in 

 the development of photography of the exhibition tanks at the 

 Aquarium have furnished the Director with interesting- numbers 

 for that department of the Society's work. The rapid increase 

 in the prices of printing papers forced the Society to secure a 

 stock of paper for the Bulletin sufficient to last until 1918. 



Annual Report. — The Annual Report for 1915 was issued 

 in its regular form, and at the usual time. 



Zoologica. — Numbers 3 and 4 of Volume II. were devoted 



