March 11, 1887.] 



8CIE]S^CE. 



251 



ago, showed that gas from wells located in dis- 

 tricts not connected with each other was similar 

 in composition, but that the percentages of the dif- 

 ferent gases present varied widely ; and more re- 

 cent analyses show that gas from wells in the same 

 'pool,' and even that from the same w^ell, is sub- 

 ject to daily and even hourly variations in com- 

 position. When it was found that the calorific 

 value of the fuel was subject to change from time 

 to time, as shown by variations in temperature of 

 the furnaces, and in the steam-pressure of boilers 

 under which it was burnt, this was at first sup- 

 posed to be due to differences in pressure ; that is, 

 in the quantity of gas delivered to the burners in 

 the fire-box. Automatic pressure regulators were 

 introduced, and the producing companies per- 

 fected a system by which the pressures were 

 maintained at a nearly constant figure, yet the 

 same variations were observed. The chemists 

 then began to examine the gas, and soon found 

 that it was extremely variable in composition. 

 The following table shows the results of ten 

 analyses of natural gas, the first four being made 

 from gas taken from the same well at different 

 times, and the others from the gas of different 

 wells in different districts : — 



' Anthropogeogi'aphie,' which gave rise to numer- 

 ous discussions, and was an incentive to many re- 

 searches of a similar kind. The new periodical 

 belongs to this class of publications. Supan sets 

 forth his plan in the introduction. He intends to 

 give a collection of reliable data arranged from 

 geographical points of view. Thus he hopes to 

 give material that will be useful by its clearness, 

 and will enable the student to investigate the his- 

 tory of commercial life. "Whoever intends to 

 study the relation between man and nature," he 

 says, " must not confine his researches to a brief 

 period. I am convinced that the geography of 

 civilization must be studied from an historical 

 stand-point. Here is the place where geography 

 and history will meet again ; this is the way in 

 which geography may become a practical science 

 in the noblest sense of the word." 



Supan arranges the statistical data contained in 

 the report of the tenth census of the United 

 States into four principal groups, and proves that 

 the north-eastern states have largely an industrial 

 population. In the central group industrial and 

 agricultural population are almost of equal impor- 

 tance, while in the southern the agricultural one 

 predominates. In the western states the influence 



Carbonic acid (CO2) 



Carbonic oxide (CO) 



Hydrogen (H) 



Marsh gas (CH4) 



Ethane (CjHe) 



Propane (CsHg) 



Nitrogen (N) 



Oxygen (O) 



Illuminating hydrocarbons 

 Ratio, C to H (weight) 



2.84 



SUPAN'S JOURNAL OF COMMERCIAL 

 GEOGRAPHY. 



The latest supplement of Petermann^s Mitthei- 

 lungen forms the first number of a journal of com- 

 mercial geography. Prof. A. Supan, the able 

 editor of the Mittheilungen, intends to give in the 

 new periodical at regular intervals a report on the 

 agricultural and industrial produce and of the 

 commerce of all continents successively. The 

 present number contains a brief introduction and 

 the report on America. The principal feature of 

 the new journal is the use of the results obtained 

 by statistical observations for geographical pur- 

 poses. German geographers of late apply much 

 of their time and work to studying the mutual re- 

 lation between geographical phenomena and the 

 history of mankind. We call to mind Ratzel's 



Archiv fur Wirthschaftsgeographie. I. Nordamerika. 

 Erganzungshef t No. 84 zu JPetermann's Mittheilungen. By 

 A. Supan. Gotha, Justus Perthes. 



of the mineral resources is characteristic. Supan's 

 discussion of the agriculture of North America 

 is accompanied by several maps which give a 

 clear idea of the distribution of cultivated land 

 and of the culture of wheat cotton, and tobacco. 

 The tables are so arranged as to show the moving 

 of the principal district of production from east to 

 west which began between the years 1850 and 

 1860. In 1850 the maximum of production was 

 found in the southern Atlantic states ; in 1860 it 

 had moved to the Mississippi-Ohio group. At the 

 same time the minimum moved from the prairie 

 states to the plateaus. The agriculture of the 

 whole east shows a permanent decrease, the 

 northern-central and the western states a perma- 

 nent increase of their relative importance, while 

 the southern states have remained stationary. The 

 rapid increase of the importance of agriculture 

 which prevailed in the Mississippi and Ohio 

 group during the last thirty years has ceased, 



