88 Kansas Academy of Science. 



Whence, multiplying both sides by {n): 



CLN P 



(19) — -- = -— - = . 000106n - . 0000009376to5 - . 00000000266n^ 



If we now multiply both sides by h^f^ we have — 



(20) P= K^r- (. 000106» - . 0000009376w'^ - . 00000000266^3) . 



= h (. 000106iV- 0000009376N? - . 00000000266Ar3) . 



An equation which will apply directly to the wheel tested and to 

 wheels built on the same lines and with dimensions proportional. 

 The same form of equation can be worked out for different makes 

 of wheels. 



PRELIMINARY REPORT ON AN INVESTIGATION OF 

 COAL-MINE EXPLOSIONS. 



By E. Haworth and C. M. Young, University of Kansas, Lawrence. 



'T^HE investigation of the causes of coal-mine explosions, of 

 ^ which this is a preliminary report, was commenced in 1906 

 by the Kansas State Geological Survey. In that year Lawrence 

 Brett, one of the seniors at the University of Kansas, took this as 

 the subject for his graduation thesis, and did a considerable amount 

 of work, with the expectation of continuing the work later. Lack 

 of funds has prevented the accomplishment of anything further 

 until the present year. In the spring of 1908 Prof. Erasmus 

 Haworth, state geologist, decided to devote the larger part of the 

 funds at the disposal of the Survey to a continuation of this inves- 

 tigation. This paper is to be considered as only a preliminarj^ re- 

 port, as the investigations discussed are not completed and others 

 are to be undertaken. But we desire to make known some of the 

 results which have been accomplished and to make a statement of 

 plans for the future. 



The work has been divided into two distinct classes; the first 

 literary, the second experimental. Along the first line, what might 

 be called a literary bureau has been established and an extensive 

 correspondence carried on with many people connected with the 

 coal mining industry both in this country and in Europe. A list 

 of questions dealing with the subject was sent to a large number 

 of coal-mino operators. Many replies have been received and the 

 results have been tabulated. These questions were intended to 

 elicit all possible information on the conditions of the coal-mining 

 industry in the different coal-fields of the United States, with the 

 idea of learning what conditions may render possible the occur- 



