October i8, 1889.] 



SCIENCE. 



273 



mitting to memory. It is in no sense an elocutionist's manual, the 

 editors having made the first test of each selection, " Is it worth 

 learning? " and the second, "Is it adapted to recitation?" The 

 book is representative of English literature, and also comprises 

 many translations from foreign sources. Its various departments 

 contain many of the familiar classics, and also many extracts from 

 late literature never before included in such a collection. It is ar- 

 ranged in three volumes, each complete in itself, and specially 

 adapted to the age for which it is intended. Volume I. is designed 

 for children from four to ten years old ; Volume II., for those from 

 ten to fourteen ; and Volume III., for the oldest students. The 

 purpose of the book is to train the memory, to educate the literary 

 taste, and to supply the student with the long-needed standard 

 collection of poetry and prose for recitation. 



— " The Batrachia of North America," by E. D. Cope, issued as 

 Bulletin No. 34 of the National Museum, embraces the results of a 

 study of the characters of the species, with their variations, which 

 has been rendered effective by the full collection contained in the 

 National Museum, and which this work thus illustrates. Besides 

 this descriptive part, there are presented the results of a thorough 

 study of the osteology of the class, based on the material contained 

 in various museums of the United States and Europe. These re- 

 sults are expressed largely in systematic form, in the belief that 

 descriptive zoology will never be complete until the structure is 

 exhausted in furnishing definitions. Wherever practicable, refer- 

 ence is made to the relations between the extinct and living forms. 



LETTERS TO THE EDITOR. 

 The Telephone for the Prediction of Thunder-Storms. 



In 1886 the writer had an experimental telephone line on the 

 Yale campus which proved to be of some value in the prediction of 



one phase of the weather. As is well known, the approach of an 

 electrical storm produces sounds in the telephone something like 

 the " sound of a distant rocket, or the quenching of a drop of 

 melted metal in water." 



One afternoon shortly after the erection of my line, on a seem- 

 ingly perfectly clear day, I heard the sounds in the telephone. 

 Although at the time there was no sign of an approaching storm, 

 two hours later the clear weather had vanished, and a severe storm 

 swept over the city. 



On another occasion, when an excursion had been planned, as 

 the weather was cloudy and rather doubtful, the telephone was 

 consulted, but gave no evidence of electrical disturbance ; and the 

 afternoon«passed " fair weather." 



In several like instances I made use of the instrument with very 

 satisfactory results. Since then I have had no opportunity for 

 continuing my observations, but I think that similar use of the 

 telephone might be of value to individuals or to local communities. 



Harvey B. Bashore. 



West Fairvlew, Penn., Oct. 14. 



Map of Niagara Falls. 



On the 88th sheet of the new " Stieler's Hand Atlas," No. 6 of 

 the United States, is a small map of Niagara Falls, which contains 

 a curious misprint. The course of the river is well shown, colored 

 red on the Canadian and green on the United States side. The 

 horseshoe fall is represented, but the American fall is obliterated. 

 The coloration for the bank extends all round Goat Island ; which, 

 however, instead of being an island, is a peninsula. In other 

 words, there is no American fall represented on the map except in 

 name. Joseph F. James. 



Washington. D.C., Oct. lo. 



INDUSTRIAL NOTES. 

 The Automatic Type-Writer. 



All are familiar with the ordinary styles of type-writer on the 

 market, and some have asked if there could not be made a type- 

 writer which should cost less and be more portable by being 

 smaller in size and weight. Several attempts have been made to 

 meet this want, and this week we have an opportunity of describ- 

 ing the " Automatic," which it is claimed serves the purpose well. 



Thus, / occupies less space than H, and H less again than 

 M. 



There are other interesting features to the machine, but we have 

 said enough to show that those interested should examine the 

 merits of the •' Automatic." 



The Offrell Dynamo. 



Although the construction of dynamos and motors has reached 

 such a state of perfection, as regards efficiency and workmanship. 



In size the " Automatic " is iii inches long, Z\ wide, and 4 high. 

 Its weight is lo pounds, and with its case, only I2|. 



The key-board of 48 keys has been designed with a view to 

 furnishing all the characters in common use. The type and type- 

 bars are so arranged that the type is inked by spring contact with 

 an ink-pad against which it rests when in repose, and the type-bars 

 are so guided in their motion as to give very accurate alignment. 

 No ribbon intervenes between the type and paper, the impres- 

 sion being thus the clearer. It is claimed for the " Automatic," 

 that, as the paper-carriage is light, as the space through which the 

 type must move is small, and as its return motion is accelerated by 

 a spring, the speed of writing is much increased. 



By an ingenious device the spacing is made to suit the letter. 



that any improvement in this direction is not likely to be made, yet 

 many of the electric machines in the market to day are far from 

 being samples of either of the above qualities ; and, to be sure, if 

 we consider them from the point of simplicity and economical con- 

 struction, there is a big margin for improvement. 



Setting out with the object in view of designing a dynamo, that, 

 with minimum expenditure of material, should give maximum out- 

 put, and at the same time the cost of its manufacture be a mini- 

 mum, Mr. Olof Offrell, electrical engineer, has designed and built 

 such a dynamo. 



To gain this purpose, only the verj' best material is used ; also 

 advantage is taken of the latest development in dynamo-building. 

 The field-magnet cores are of the very best wrought iron, the pole- 



