August 18, 1905.] 



SCIENCE. 



223 



proper succession of crops on the same land, 

 the best sources for good seeds, irrigation, and 

 the raising of stock. They are made ac- 

 quainted with improvements and new inven- 

 tions in agricultural implements the adoption 

 of which can be recommended. They are 

 taught the rudiments of bookkeeping and other 

 commercial knowledge essential for the up-to- 

 date farmer. In the spring, after these farm- 

 ers have returned to their work in the fields, it 

 becomes the duty of the teachers who in- 

 structed them during the winter to travel from 

 county to county and to act as advisers to the 

 farmers. Much good results from the travels 

 of these wandering teachers. By practical 

 suggestions to the farmers they induce them to 

 make valuable improvements in the cultiva- 

 tion of their farms. The wandering teacher 

 helps to form cooperative clubs for the joint 

 interests of a number of farmers in one dis- 

 trict. From time to time the teacher has to 

 lecture in these clubs on any subject practical 

 or scientific which might prove of interest to 

 the members. These visits and lectures to the 

 different districts are entirely free to the peo- 

 ple, since the state assumes all expenses. 

 There is probably no other country in the world 

 in which so much is done by the state for its 

 rural inhabitants as is the case in Bavaria. 

 Other German states have these agricultural 

 schools, but their teachers are not sent in such 

 a practical way direct to the places where they 

 can do the most good, as is done here. The 

 results of this commendable care have been 

 very gratifying. 



Concerning the exhibition held recently in 

 London in connection with the Optical Con- 

 gress, Nature says : The exhibition of optical 

 and scientific instruments which is being held 

 during the present week at the Northampton 

 Institute, Clerkenwell, E.C., in connection 

 with the optical convention, presents many 

 features of interest, and all who have had any 

 experience in the use of an optical instru- 

 ment, from the wearing of a pair of spectacles 

 to the handling of an accurate spectrometer, 

 will find something to repay the trouble of a 

 visit to Clerkenwell, still the center of the 

 optical industry. While the number of actual 

 novelties offered is not, perhaps, very large, 



there are few classes of instruments unrepre- 

 sented, and though the names of certain im- 

 portant firms are conspicuously absent from 

 the list of exhibitors, the exhibition as a whole 

 may be taken as well representative of the ac- 

 tivities of the British manufacturers of optical 

 and other scientific instruments. In the main 

 of an optical character, the scope of the exhi- 

 bition has been extended to cover such other 

 scientific instruments as are usually manu- 

 factured by optical instrument makers. 

 Meteorological instruments and thermome- 

 ters, mathematical and drawing instru- 

 ments and calculating machines, and labora- 

 tory apparatus generally, are thus included. 

 Electrical measuring instruments, however, 

 are not shown. It is for many reasons to be 

 regretted that the exhibition has been confined 

 to the work of British makers; a foreign sec- 

 tion would have had much interest for the 

 ordinary visitor, and would have been of great 

 educational value both to the British manu- 

 facturer and his competitors; we understand, 

 however, that the limitation was dictated by 

 considerations as to space, and the necessity of 

 restricting the magnitude of a somewhat novel 

 undertaking. In the catalogue which has been 

 prepared in connection with the exhibition, 

 the convention committee is to be congratu- 

 lated on having produced a volume which 

 should be of considerable value as well to the 

 user of scientific instruments as to the firms 

 whose instruments are there described. The 

 volume is not confined to apparatus actually 

 exhibited; the aim has been to provide a con- 

 venient work of reference generally descriptive 

 of the productions of British firms, and in 

 which particulars as to the types offered by 

 different makers of any special instrument 

 may be readily found. To this end the instru- 

 ments have been arranged in classes, which 

 are in many cases further subdivided, and 

 in addition to a table of contents, an alpha- 

 betical list of exhibitors, with general in- 

 formation as to their manufactures, and an 

 index of instruments have been provided. A 

 short introduction to each class furnishes 

 some particulars as to the instruments included 

 thereunder, with notes as to recent advances 

 in the mode of construction. 



