December 13, 1894J 



NA TURE 



'57 



in addition to being qualitatively applicable, are also quantita- 

 tively sufficient to produce the result. {Annals of Mathematics, 

 vol. viii. No. 6.) With this application in view, he has deter- 

 mined the course in the air of a free heavy plane subjected to 

 definite wind pulsations. For a period of action of ten seconds, 

 the following result was obtained " without any internal 

 source of energy, during the lo seconds of alternate calm and 

 wind, the plane has in the first 275 seconds made a descent of 

 36 feet, and in the remaining 7-25 seconds has risen 46-9 feet, 

 travelling at the same time horizontally a distance of 251 feet, 

 of which 154 feet is made against the wind. In addition, the 

 relative velocity of the plane and wind (58"9 feet per second) at 

 the end of this period is sufficient, if the wind continue with 

 the same velocity, to yield a considerable further ascent before 

 the vertical component of pressure is reduced to such an extent 

 that it no longer exceeds the weight of the plane under the con- 

 stant angle of inclination." Though the conditions of the 

 problem solved by Prof. Curtis are seldom met with in nature, 

 the results he has obtained have a very important bearing upon 

 mechanical flight. 



A NUMBER of papers of considerable value are published in 

 the MUtheihingen der Prahistorist hen Commission Jer Kais. 

 Akademic der Wissenschaftcn. (Bd. I, No 3. V.'ien, 1893). 

 J. Szombathy describes the ceramics discovered by him in a 

 tumulus at Langenlebarn, in Lower Austria. lie points out that 

 double and multiple vessels were common in the finds of the 

 bronze period and first iron age of the eastern Mediterranean 

 countries, especially in Cyprus and Troas, somewhat rarer at a 

 later time in the graves of the first Italian iron age, and still 

 more rare in the later graves of the Ilallstatt period of the 

 Austrian Alps and of Central Europe. The doubling arose 

 from the gradual increase in diameter of the lower portion 

 of the long cylindrical neck of an earlier type of vessel. 

 Dr. M. Hoernes gives a study of the forms of various pre- 

 historic objects which he has observed in the museums of 

 North-east Italy. Amongst other objects he refers to bronze 

 and iron knives in the museum at Padua. The resemblances in 

 the handles and ornamentation of certain clay vessels leads 

 him to the conclusion that the culture of the bronze age 

 of Northeastern Italy extended to the East, and in- 

 cluded Bosnia-Herzegovina and Istria ; but from this he 

 does not deduce an ethnical relationship. In the broni'.e period 

 of Eastern Upper Italy not only were pile-dwellings inhabited, 

 but mounds as well, as in Istria and Bosnia-Herzegovina. Even 

 if related pile-structures are not to be found in the north-west 

 of the Balkan Peninsula, the difference in the mode of life is 

 counterbalanced by other considerations. The evolution of the 

 Italians and the Illyrians later diverged in the historically well- 

 known way. He would add the Ligurian people as belonging 

 to the same culture group of that age ; this culture-uni'y 

 separated these people from other peoples living further north 

 and south of this zone. Dr. Hoernes also describes some 

 triangular and other ornaments, human and animal forms, 

 especially those with associated birds, as well as bronze and 

 iron fire-dogs. Prof. R. Trampler writes on the oldest graves 

 in the Briinnen Valley district ; and F. Heger, on finds from pre- 

 historic and Roman times in Lower Austria. The author of this 

 well-illustrated paper states that there was a pure bronze age 

 in the district of Upper and Lower .Vustria, which had points 

 of relationship with the Western finds, and especially with those 

 in the North and East. 



A CURloi;s formation is illustrated in the first annual report 

 of the Iowa Geological Survey, published a few months ago. 

 Good exposures of limestone rocks are found .ill along the 

 Mississippi from Keokuk to Burlington, in south-eastern Iowa. 

 The limestone often stands out in overhanging cliffs over the 

 NO. 1311, VOL. 51] 



softer shale beds beneath, and gives the appearance of a cas- 

 cade, as shown in the accompanying illustration, which is reduced 

 from a plate in the report. The Survey was only established 



in 1892, but the report shows that a large amount of useful 

 information, of great economic interest to the people of the 

 State, has already been collected. 



The volume referred to in the foregoing note showed us that 

 the publications of the Iowa Geological Survey were to be of a 

 high character. The second volume, which reached us a few 

 days ago, goes to confirm this view. It is a description of the 

 coal deposits of Iowa, by Dr. C. R. Keyes, and is a model of 

 what a general report should be. With text running into more 

 than five hundred quarto pages, eighteen full-page plates of a 

 high quality, representing interesting formations in connection 

 with the coal-measures, and over two hundred figures in the 

 text, the volume is an attractive handbook for the coal-miners 

 of Iowa. It is not a detailed account of the geological features 

 of the coal districts — that will follow when sufficient facts have 

 been accumulated ; it is rather a preliminary report, somewhat 

 general in character, but sufficient to supply temporarily the 

 demand for information pertaining to the coal deposits of the 

 State. Separate volumes will be devoted to practical mining 

 in Iowa, and to a description of the uses and properties of Iowa 

 coals. We offer our congratulations to Dr. Keyes and the 

 geological corps with which he is associated. May their inten- 

 tions with regard to future work be satisfactorily realised. 



In the current number of the Zoologischer Anzeiger (No. 

 462), Dr. Arnold Graf records some novel observations made by 

 him in the course of some experiments on the effects of com- 

 pression on the segmentation of the egg of the sea-urchin 

 Arbacia. Driesch has already shown that compression of the 



