Apkil 13, 1917] 



SCIENCE 



363 



to his purpose, i. e., filling a given space with 

 ornament pleasing to the eye. 



Decorative art is limited by space, mate- 

 rial, etc., and its interest often consists in 

 the artist's effort to use these limitations; 

 while the comparative freedom of pictorial art 

 often causes it to degenerate into imitation 

 — which, of course, is not art at all. 



As the technic of art is properly a science, 

 these remarks may not be entirely out of place. 



Maegaeet Aemsteong 



the preservation of records 

 To THE Editor of Science: On reading the 

 article on " Our Duty to the Future," by 

 Professor C. E. Vail, in the December num- 

 ber of the Scientific Monthly, it occurred to 

 me that we have at hand, available without 

 special expense, better means of leaving per- 

 manent records for the future than any of our 

 predecessors. Practically all printing is done 

 from electrotypes; these electrotypes are made 

 of metals that are not readily corroded by 

 atmospheric action and under proper storage 

 conditions would be very permanent. 



In the production of practically all great 

 books, or other records, engravings, etc., elec- 

 trotypes are used. After serving their pur- 

 pose in printing the edition many times they 

 are but slightly worn and could be stored 

 compactly in fire-proof and earthquake-proof, 

 dry vaults. Sets of electrotypes, such as those 

 employed in printing the Encyclopedia Britan- 

 nica, and other reference works, would provide 

 for future generations a considerable knowl- 

 edge of almost everything of importance per- 

 taining to this era. 



Generally speaking, the preservation of rec- 

 ords in this way would cost no more than the 

 bullion price of the metal involved in the 

 plates, as otherwise the plates would be re- 

 melted and the metal used over. 



John S. Wright 



guide to the mosses of the Northeastern 

 United States " according to its subtitle or, as 

 the cover states, " This handbook of mosses — 

 the first intended for use without a microscope 

 — throws open a new and fascinating field of 

 study to the amateur botanist and nature lover. 

 Keys to 80 genera and descriptions of over 150 

 species are given." In view of the limitations, 

 and considering how difiicult it is to really 

 know the mosses thoroughly, Mrs. Dunham's 

 conscientious eilort to introduce a few of our 

 most abundant and easily recognized genera 

 and species to a wider acquaintance will cer- 

 tainly lengthen the season of out-door pleas- 

 ures and interests for those who love nature 

 at all times of the year ! For " the mosses and 

 lichens love the damp shade and the wet frosty 

 season when other plants fade." To acquire 

 even a bowing acquaintance with 80 out of the 

 200 genera represented in our flora and grow 

 to recognize 150 species out of nearly 3,000, is 

 to learn to have eyes that see and appre- 

 ciate the subtler beauties of form and color. 



The drawings in the text and the full-page 

 illustrations will be found helpful and with 

 the exception of a few indispensable technical 

 terms the book is free from pedantry and un- 

 necessary verbiage. E. G. Britton 



New Toek Botanical Garden 



SCIENTIFIC BOOKS 



How to hnow the Mosses. By Elizabeth 

 Marie Dunham. Boston: Houghton, Mifflin 

 Co., 1916. 28Y pages, illustrated. $1.25. 

 This little book is intended as "a popular 



SPECIAL ARTICLES 



THE EFFECT OF FINENESS OF DIVISION OF 



PULVERIZED LIMESTONE ON THE YIELD 



OF CRIMSON CLOVER AND LIME 



REQUIREMENT OF SOILS 



The practical significance which attaches to 

 studies in the application of lime to soils is 

 responsible for experimentation with pulver- 

 ized limestone of varying degrees of fineness. 

 Frear^ cites, together with his own experi- 

 ments, the comparatively few investigations 

 pertaining to this problem. It has been stated 

 by some authorities that limestone passing a 

 10-mesh sieve is satisfactory for field practise, 

 while others have advocated material passing a 

 60-mesh sieve, some claiming that even finer 

 pulverization is to be preferred. The following 

 experiments were planned in 1914 to throw 



1 Frear, W., ' ' Sour Soils and Liming, ' ' Dept. 

 Agr. Penn. Bui. 261, 1915. 



