866 



SCIENCE. 



[N. S. Vol. V. No. 127. 



the glass itself must be kept absolutely 

 clean, only filtered water to be put upon it, 

 and the diamontine must invariably be pro- 

 tected from the dust. 



A knife is sharpened when its edge ap- 

 pears smooth and straight under a magnify- 

 ing power of 40-50 diameters. 



When section cutting began a razor was 

 the sharpest of familiar tools, and so it 

 happened that for years razors were iised 

 not only for free-hand cutting, but also for 

 microtomes. When knives began to be 

 made specially for microtomes the razor 

 type of thin blade was followed. We now 

 know that the razor is the worst possible 

 model for a microtome knife and that the 

 chisel pattern is infinitely superior, because 

 a thin blade is elastic, while a thick blade 

 is rigid. With small objects or soft tissues 

 the resistance may be so slight that the 

 razor will cut them satisfactorily. Or, 

 again, if the sections are thick the error 

 of the razor may be unimportant, but for 

 very thin sections, or for cutting difficult 

 objects, the new heavy tj'pe of knife may 

 fairly be said to be indispensable. 



Chaeles Sedgwick Minot. 



Haevaed Medical School. 



XII. DEVTSCHEB GEOGRAPHENTAG, JENA, 

 1S97. 



During the late Easter vacation there 

 were gathered together, in the charming 

 little university town of Jena, a large num- 

 ber of the German Scientists whose work 

 touches more or less closely the field of 

 geography. When one considers the va- 

 riety of subjects represented he must put 

 the question : What is Geography ?— What 

 has it been in the past and to what future 

 fields is the present aspect of the science 

 leading. To consider this theme, at length, 

 is not the intention of the writer in giving 

 a short account of this Congress of German 

 Geographers, but he would like to use this 



question as a connecting thread in the fol- 

 lowing lines. 



There were nearly 600 members and as- 

 sociates in attendance, making this Geo- 

 graphentag the third largest in numbers of 

 this series of most successful gatherings. 

 Only Berlin and Vienna have had a larger 

 attendance, and so it was said that Jena 

 should be rated as a city with a million in- 

 habitants. All those present were not from 

 Germany, as eleven other nationalities 

 were represented, these justly famous scien- 

 tific gatherings naturally attracting for- 

 eigners. The addresses given are of such 

 merit and given by such men as to induce 

 many to come to hear, but it is not forgot- 

 ten by the committees in charge that the 

 most important feature of such gatherings 

 is to bring the workers in various fields to- 

 gether, and to give them opportunities for 

 conversation and consultation. The four 

 and a half days were very happily arranged 

 so as to supply a combination of attractions 

 suited to the wants of all. 



Under the presidency of Geheimrath 

 Neumayer the members were led to con- 

 sider the investigation of the region of the 

 South Pole, and were shown that while 

 very little in the way of actual exploration 

 had been done by the com mission , which was 

 appointed at the XI Deutschen Geographen- 

 tag in Bremen, still a large amount of ma- 

 terial had been collected, and the way was 

 being prepared for pioneer work in this 

 little mapped region. Outline cartography,^ 

 or the separation of land from water areas, 

 is one of the early stages of geographic 

 science. It is naturally followed by expe- 

 ditions over land in the less known por- 

 tions of the continents. This second phase 

 of the science was represented at Jena by 

 the three following papers : Expedition to 

 Central Brazil, by Dr. Herrmann Meyer, of 

 Leipzig ; German Investigations in Asia 

 Minor, by Dr. Heinrich Zimmerer, of Miin- 

 chen ; Journey through Syria and Ana- 



