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THE POPULAR SCIENCE MONTHLY. 



pressed to a pressure of forty-five pounds 

 above the atmosphere is delivered into pipes 

 which are laid like gas-pipes over four miles 

 of streets. The works had only left the 

 hands of the contractors, when there were 

 forty customers for air-power, some of them 

 at a distance of a mile and three quarters 

 from the compressing station. The loss of 

 power by friction in the pipes is so light 

 that no ordinary gauge will show it. The 

 engines of the consumers vary in size from 

 half a horse-power up to fifty horse-power. 

 Under the system of Hughes and Lancaster, 

 by which compressed air may be applied to 

 tramways, a pipe is laid in the street for the 

 supply of compressed air to the cars, which 

 carry the machinery for propulsion. Any 

 gradient which a locomotive can mount can 

 be ascended by the cars, and fresh supplies 

 of air can be taken in without stopping the 

 cars. 



Petroleum as an Explosive. Experi- 

 ments by Peter T. Austen exhibit petroleum 

 as an explosive of the dangerous class. It 

 evolves inflammable gases at ordinary tem- 

 peratures, and some of them are not liquefied 

 by a considerable reduction of the tempera- 

 ture. The author applying a match to a 

 flask containing crude petroleum at zero 

 Fahrenheit, the flask was filled with a blue 

 flame. Since the evolution of gas is in- 

 creased by shaking the oil, an inflammable 

 gas must accumulate in the vacant parts of 

 car-tanks, in a condition more or less fa- 

 vorable to explosion. If the gas in contact 

 with the petroleum becomes ignited, the oil 

 will, in most cases, take fire unless the body 

 of the liquid is very cold ; and the danger 

 increases as the temperature. The behavior 

 of a tank of petroleum under pressure has 

 not been much studied ; but all know how 

 tinder may be ignited in a " fire syringe " 

 an effect of simple compression. The lubri- 

 cating oil of the piston also takes fire at a 

 temperature of about 300. The volatile 

 gases of petroleum may be ignited at a lower 

 temperature. If the mixture of air and va- 

 por over petroleum is compressed to one 

 fourth its volume, the temperature will be 

 raised to 429 from zero, and to 499 from 

 70 Fahr. It follows, therefore, that if an oil- 

 tank filled or partly filled with such a mixt- 

 ure is suddenly compressed in such a way as 



greatly to reduce its volume, the gas, and 

 probably the oil, will be ignited by the com- 

 pression. This might happen in r. case of 

 telescoping or of a fall of the tank. If a 

 tank nearly filled with oil were suddenly 

 compressed, the resistance offered by the 

 liquid would heat it sufficiently to cause an 

 evolution of its lighter hydrocarbons in suf- 

 ficient quantity to create a dangerous press- 

 ure within the tank. This might happen 

 when, the car being stopped in a collision, 

 the oil is suddenly hurled against the front 

 end of the tank. The author concludes 

 that precautions against explosion are ne- 

 cessary in the transportation of crude petro- 

 leum. 



Alcohol as a Cause of Disease. Dr. 



Lewis D. Mason, of the Inebriate Asylum, 

 Fort Ilamilton, N. Y., discussing The Eti- 

 ology of Dipsomania and the Heredity of Al- 

 coholic Inebriety, determines as facts that 

 alcoholism in progenitors will produce physi- 

 cal and mental degradation in their descend- 

 ants, with the disorders that arise from a de- 

 fective nerve organization ; and all grades 

 of mental weakening, from slight enfeeble- 

 ment of intellect to insanity and complete 

 idiocy ; and that the laws regulating these 

 changes are similar to those that govern con- 

 genital degenerative changes from other 

 causes. The offspring of the confirmed 

 drunkard will inherit either the original vice 

 or " some of its countless Protean transfor- 

 mations." In another paper on Pathologi- 

 cal Changes in Chronic Alcoholism Dr. Ma- 

 son exhibits alcohol as modifying the serum 

 and the anatomical elements of the blood, 

 besides being an irritant and directly produc- 

 ing modification and degeneration of tissue, 

 and therefore as being most evidently a dis- 

 ease-producing agent. Contrasting the little 

 progress that has been made in the study of 

 the pathology of chronic alcoholism and of 

 the diseases incident to alcoholism with the 

 great advance that has been achieved in 

 knowledge of microbic diseases, he adds : 

 " Alcohol has not any microbe, but the grand 

 total of its mortality will exceed the com- 

 bined effect of all the bacteria that have ever 

 passed the microscopic field or developed in 

 the culture-tube of the bacteriologist." The 

 subject is now, however, beginning to receive 

 some of the attention it deserves. 



