94 Kansas Academy of Science. 



mixture would burn in the air. It is therefore evident that black 

 powder, if used in a mine under such conditions as to produce 

 large quantities of combustible gases, may be a source of great 

 danger, especially if the mine contains explosive dust. The im- 

 portance of the method of mining is evident in connection with 

 this point. In the room-and-pillar method and its modifications 

 from one to three shots are fired in one room. The gases evolved 

 are therefore mixed at first with only a small quantity of air, and 

 if these gases contain a sufficient quantity of combustibles an ex- 

 plosive mixture may result, while if the powder gases were mixed 

 with a larger quantity of air the mixture would not be explosive. 

 Explosions of mixtures of powder gases and air formed under these 

 conditions are of frequent occurrence and may give rise to explo- 

 sions of great importance. 



The production of carbon monoxid during mine fires should 

 also be mentioned, as some explosions have undoubtedly been due 

 to the presence of carbon monoxid thus produced. A severe ex- 

 plosion at Hanna, Wyo., was apparently caused in this way. 



As stated previously, the work is not finished, and this is to be 

 regarded only as a preliminary report, not stating final conclusions, 

 but constituting a record of progress. It is intended that this in- 

 vestigation shall be continued until as many as possible of the 

 problems connected with it shall have been attacked and, it is 

 hoped, solved. It is recognized that the question is a complicated 

 one and that it deserves all of the serious attention which it is now 

 receiving. The canvass of the literature of the subject will be 

 continued with the idea of compiling as complete a bibliography 

 as is possible. The laboratory experiments will be continued, es- 

 pecially along the lines of the investigation of coal-dust and of ex- 

 plosives. Up to the present time nothing but black blasting- 

 powder has been studied. It is our desire to make a study also of 

 the safety powders now being placed upon the market. It is also 

 our intention to carry on a set of investigations at mines, testing 

 the action of the explosives in actual use and examining the mine 

 atmosphere. 



