FRAGMENTS OF SCIENCE. 



569 



workmen's baths said to have been estab- 

 lished in Germany prior to 1896. In the 

 case of school baths in Germany, the aver- 

 age cost of a warm shower bath is said to be 

 one quarter of a cent, and it is safe to say 

 that, leaving the interest on the plant out of 

 account, the cost in the workmen's baths is 

 about the same, or even less. The cost of 

 the latter baths varies all the way from three 

 hundred and fifty dollars to five thousand 

 dollars — a very good twelve-cabin shower 

 bath, with one hundred and seventy towels 

 and bath caps, having been built at Dalken 

 in the Diisseldorf district for three hundred 

 and forty dollars. Of the great importance 

 of cleanliness in promoting hygienic condi- 

 tions, it is hardly necessary to speak, and we 

 hope that a similar movement may spring up 

 among the mill owners and large manufac- 

 turers in this country. The public schools 

 are also worthy the close attention of our 

 public-school officials. 



Explosiveness of Dynamite. — From an 

 article in Industries and Iron, we take the 

 following : In the early days of dynamite 

 the mischievous and often fatal doctrine 

 was thoughtlessly promulgated that under 

 the influence of fire that explosive would 

 only burn, and that nothing would cause it 

 to explode except the application of a prop- 

 er detonator. Notwithstanding the efforts 

 which have been made to cause the public 

 to unlearn this foolish doctrine, it still lin- 

 gers. The doctrine preached by those who 

 know anything about the matter is that ex- 

 plosives are only comparatively safe at the 

 best, and then only so long as they are treat- 

 ed as absolutely dangerous. There is no re- 

 liance whatever to be placed on the theory 

 that dynamite and many of its congeners 

 can be burned without exploding. This has 

 been illustrated over and over again with 

 fatal results, and the ignorance, crass stu- 

 pidity, and recklessness occasionally shown 

 by those accustomed to the daily use of high 

 explosives are really incredible. Were the 

 author of a highly flavored story to intro- 

 duce into his plot the instantaneous death of 

 a newly married couple by an explosion of 

 dynamite in the stove of their sitting room, 

 the explosion being brought about by the 

 bridegroom's brother baking the dynamite in 

 the oven, the author would probably be ac- 



cused of going beyond the bounds of prob- 

 ability after the sensational, and yet this 

 combination of circumstances did actually 

 occur m a mining district in England. The 

 ingenuity exercised in devising means for 

 thawing dynamite in the most unsafe way 

 possible is certainly very remarkable. This 

 thawing-out process is the most fruitful cause 

 of accidents with dynamite. The dynamite 

 becomes inert at about 40° F., and, while 

 this is a very valuable property for trans- 

 portation purposes, it plainly also has its dis- 

 advantages. To thaw these cartridges tin 

 warming pans constructed on the principle 

 of the glue pot should be provided. This 

 keeps the explosive away from any possible 

 contact with the fire, and prevents the possi- 

 bility of an excessively high temperature. 



Radiography in Medical Practice. — Dr. 



Francis H. Williams, in an address before 

 the Association of American Physicians, 

 gives an interesting account of his year's work 

 with the X rays, and shows that they must 

 now be accepted as one of the valuable in- 

 struments in the general physician's equip- 

 ment. The varying resistance which the 

 different tissues of the body offer to the 

 passage of the X rays depends upon differ- 

 ence in bulk and chemical composition. The 

 soft tissues of the body contain a large per- 

 centage of water, so that they offer about 

 the same resistance as an equal thickness of 

 the latter. The rays, however, pass through 

 air much more readily than they do through 

 water. It is this fact which gives the X ray 

 its special value in physical examinations of 

 the chest. The radiograph of the normal 

 chest shows two clearly marked out lungs, 

 divided by a dark line representing the 

 sternum, and crossed by dark horizontal 

 bands, the ribs. The lower internal portion 

 of the left lung is partially obliterated by 

 the heart, as is also a small segment of the 

 lower portion of the right lung. This picture 

 is normally very sharp and unmistakable, 

 so that any abnormal state of affairs in the 

 lungs and any variation in the size or posi- 

 tion of the heart are readily made out by the 

 use of the fluoroscope. In his summary Dr. 

 Williams claims that the X rays, and more 

 especially the fluoroscope, have already proved 

 to be an important addition to the ordinary 

 methods of physical examination, and that 



