32 SCIENCE PROGRESS 



kind of observation required is somewhat different from that 

 demanded by the sciences of chemistry and physics, and each 

 kind supplements the other, a combination of the two being 

 desirable for the proper quickening of the observing power. 



The great importance of developing the faculty for observing 

 the phenomena which are within the domain of the ptrysical 

 geographer is becoming more and more recognised, but upon 

 this head something will be said in a later part of this article. 



Let us now pass to the consideration of the value of our 

 subject as a means of development of the reasoning powers. 

 We find here a marked difference between the influence of 

 physical geography and that exacted by the study of chemistry 

 and physics. 



The sciences are sometimes divided into two groups according 

 as they are "certain" or "uncertain" — the former being con- 

 cerned with matters which are capable of mathematical demon- 

 stration, while the natural sciences fall into the latter group. 

 But the uncertainty of the sciences of this group varies in 

 degree, and we might speak of the less uncertain and the more 

 uncertain studies. In the former we should place chemistry 

 and physics, and in the latter physical geography. The un- 

 certainty of the latter constitutes a danger as far as education 

 is concerned, but also gives it a very real value. The danger 

 to be avoided is that of loose reasoning, and it is one which 

 concerns the teacher rather than the taught. The teacher 

 should utilise this very danger as a means of instruction, 

 pointing out that an explanation may contain the truth, and 

 yet not " the whole truth and nothing but the truth." Take the 

 case of the formation of those coral islands which are known as 

 atolls. The theory put forward many years ago by Darwin to 

 explain these structures on account of its simplicity and beauty 

 gained general acceptance, and was often explained in elementary 

 text-books without the reservation which its illustrious author 

 himself made. It was subsequently attacked, but that it contains 

 part of the truth is clear. Probably not the whole truth, 

 however, for, as Huxley once remarked (as recorded by Prof. 

 Judd) : " I am convinced, from all that is being done now, 

 that we shall not find any simple easy explanation of all coral 

 reefs ; that the study of coral reefs is one of the very greatest 

 complexity; that the conditions under which they were formed 

 would have varied greatly in different cases ; and that one 



