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THE POPULAR SCIENCE MONTHLY. 



the symptoms of hydrophobia, and that, 

 were it not for the common belief in canine 

 virus, the spasms and other manifestations 

 of the disease would not supervene. This 

 view is confirmed by the fact that young 

 children, who are not acquainted with the 

 common belief as to hydrophobia, may be 

 bitten by mad dogs and escape spasms and 

 madness. He adds : 



" If we are able, as in olden times, and 

 in the case of children, to instruct or induce 

 men to be perfectly quiet after they are bit- 

 ten by a rabid dog, not to tremble or be 

 frightened, but to banish anxiety, to control 

 their imagination, and, with patience and 

 hope, to look forward to recovery, and also 

 to persuade the well to remain with the un- 

 fortunate one, and not to run away, but to 

 cheer him in the hour of trial, then the 

 means may have been discovered by which 

 the effects of the accident are to be ban- 

 ished, and the poison in the wound neutral- 

 ized." 



Odorous and Liqncfiablc Gases: what 

 Gases may be liquefied. A writer in the 

 Pharmaceutical Journal notes a remarkable 

 relation between the odor of gases and their 

 reducibility to the liquid or solid state. 

 Thus oxygen, hydrogen, and nitrogen, which 

 have no odor, cannot be reduced either by 

 pressure or by cold. On the other hand, 

 chlorine, which has a very strong odor, is 

 easily condensed to a liquid. Again, the 

 protoxide of carbon, being odorless, cannot 

 be condensed, while the dioxide or carbonic 

 acid, which has a faint, pleasant, and pun- 

 gent odor, can be reduced to a liquid, and 

 even to a solid state. Nitrous and nitric 

 oxide, the latter of which is odorless, show 

 similar phenomena. An exception to the 

 general rule, that gases which are odorous 

 are condensible, is furnished by acetylene, 

 which, though having a faint garlic smell, 

 has never been condensed. Usually con- 

 densability stands in a direct ratio to the 

 strength of the odor possessed by a gas. 

 Thus, sulphurous acid, which has a most 

 intense odor, becomes a liquid under a 

 pressure of two atmospheres, at 15 Fahr., 

 while nitrous oxide, which has but a faint 

 smell, requires fifty atmospheres, and a 

 temperature of 7.2 F. A few gases hav- 

 ing a fetid odor are exceptions to this law, 



but it holds good so generally, that a list of 

 gases, arranged according to their reduci- 

 bility, and another list arranged according 

 to their properties of smell, will show a 

 rough though marked coincidence. 



The Spectroscope and the Bessemer Pro- 

 cess. Prof. Tidy, in a lecture on the spec- 

 troscope, thus briefly describes its impor- 

 tant practical application in the Bessemer 

 process : " Cast-iron contains a great amount 

 of carbon, and in the Bessemer process this 

 carbon is got rid of by burning it out of the 

 molten iron with a blast of atmospheric air. 

 The fluid cast-iron is placed in a large re- 

 tort lined with refractory clay. This retort, 

 the converter as it is called, turns on a pivot. 

 Through the pivot a tube passes in connec- 

 tion with a very powerful blowing apparatus, 

 by which air can be blown into the molten 

 iron. That air burns out the carbon, the 

 heated gases issuing as a flame from the 

 converter. Now, it is very important to 

 stop that blowing process directly the time 

 arrives. Ten seconds too soon, or ten sec- 

 onds too late, and the charge is spoilt. Ex- 

 perience, I grant you, does guide the work- 

 er, but experience is a costly thing ; and 

 this I am confident of: laud experience as 

 you will, it will not weigh down the scale 

 when we have in the opposite pan exact 

 scientific experiment. The Bessemer flame, 

 as it issues from the converter, is examined 

 by the aid of the spectroscope. Numerous 

 substances are visible sodium, potassium, 

 iron, hydrogen, carbon, etc. All of a sud- 

 den, in a second, the carbon-lines disap- 

 pear, and that is the moment when the air- 

 blast must be turned off, for now the carbon 

 is burnt away, and the iron is converted." 



New Material for Illuminating Gas. Le 



Gaz, the gas-light journal of Paris, calls the 

 attention of the directors of gas-works to a 

 new illuminating material, vegetable pitch. 

 This material is made by the Patent Oil and 

 Stearine Company, of England, from the 

 residues of the manufacture of olive, palm, 

 cocoa, and other oils. In England it is 

 widely used, being employed in gas-works 

 in connection with coal, with a view to aug- 

 ment the volume of gas, as well as its illu- 

 minating power. The London Gas-light Com- 

 pany constantly employs it, mixing it in 



