To Readers of THE POPULAR SCIENCE MONTHLY: 



Without flattery it is safe to say that 

 you have one advantage over other book 

 buyers; you know the "literature" or bib- 

 liography of your specialty better than they 

 know any one thing about the world of 

 books. You do not buy or read a book in 

 your special line that is written by one who 

 is not a specialist of high standing in thai 

 subject. But when you buy a book on some 

 other subject, scientific or non-scientific, you 

 are usually no better off than the person 

 who knows nothing about any kind of 

 books. 



But in deciding whether or no you are 

 to buy a general work of reference you can 

 apply, with some degree of certainty, the 

 same test that you use in buying books in 

 your special field of study and research. The 

 contributors in your field to the new Encyclo- 

 paedia Britannica are the world's greatest 

 men in that field, and you know them by 

 name and by that reputation. From this you 

 might infer that the whole book is written 

 by equally great authorities, and that other 

 departments of the Encyclopaedia Britan- 

 nica were handled as efficiently as the one 

 of which you can make a personal test. 

 But let us not leave this merely to inference. 



When this advertisement was being 

 planned, a copy of the weekly SCIENCE con- 

 taining the volume index was on the writer's 

 desk. He was measuring the type page to 

 see how many words he could get into the 

 space. Before him was a list of the princi- 

 pal contributors to the Britannica in natural 

 science ; and these same names began catch- 

 ing his eye in the index to SCIENCE. 

 Considerably more than half of the select 

 list of Britannica contributors were men- 

 tioned in one way or another in the pages 



of SCIENCE during the last six months. 

 During that time several had received high 

 honors — medals of the Royal Society, the 

 Royal Meteorological Society, the Liver- 

 pool School of Tropical Medicine, the Royal 

 College of Physicians or some other honor 

 on completing many years of life or of 

 great service; others wrote important new 

 books on subjects as diverse as Organic 

 Chemistry andsThe Geology of Soils, reviewed 

 in SCIENCE; or their lectures or addresses 

 — on the Piltdown skull or on the value of 

 the Natural Sciences — were reported in 

 SCIENCE; or they wrote book reviews 

 on Mineral Deposits or appreciations of 

 Noguchi's work on infective diseases ; and 

 a few of them, including a great British 

 physician and the director of the Cam- 

 bridge University Astronomical Observa- 

 tory, died during the period. 



In other words if you looked over the 

 list of contributors to the Britannica in 

 your field of special study you would find 

 them the authorities picked from the whole 

 world. The same experiment tried by any 

 of your colleagues, no matter how widely 

 different his special field may be from yours, 

 would result in the same way. Whether 

 you argue from what has been said of the 

 contributors to the Britannica whose names 

 so constantly crop up in SCIENCE, or 

 whether you take first your test of the men 

 in your special field and then like tests 

 made by other experts in the same way but 

 in other branches of science — the result is 

 the same. And not only in science, but in 

 literature, art, history, or any other field, 

 the authorities who contributed to the 

 Britannica are the authorities known all 

 over the world by the special students of 

 each branch of knowledge. 



" In the domain of science the Encyclopaedia Britannica loses nothing of its 

 authoritative character." — The Review of Reviews. 



