378 



THE POPULAR SCIENCE MONTHLY. 



will peiiiiit. These investigations are expect- 

 ed to be made with critical and scientific ac- 

 curacy, and will consist in the mintite analy- 

 sis of a somewhat limited number of speci- 

 mens, ami the precise determination of me- 

 chanical and physical properties, with a 

 view to the detection and enunciation of the 

 laws connecting them with the phenomena 

 of resistance to flexure, distortion, and rup- 

 ture. 



The Board will be prepared to enter 

 upon a more general investigation, testing 

 such specimens as may be forwarded to the 

 President of the Board, or such as it may 

 be determined to purchase in open market, 

 immediately upon the completion of the 

 apparatus ordered, at which time circulars 

 will be published giving detailed instructions 

 relative to the preparation of specimens for 

 test, and stating minutely the information 

 which will be demanded previous to their 

 acceptance. 



The following is a list of the subjects to 

 be investigated by the standing committees, 

 as given in the circular issued by the Board : 

 Abrasion and Wear ; Armor-Plates ; Chem- 

 ical Research ; Chains and Wire Ropes ; 

 Corrosion of Metals ; Effects of Temper- 

 ature ; Girders and Columns ; Iron, Mal- 

 leable ; Iron, Cast ; Metallic Alloys ; Ortho- 

 gonal Simultaneous Strains ; Physical Phe- 

 nomena ; Reheating and Rerolling; Steels 

 produced by Modern Processes ; Steel for 

 Tools." 



Insulation of Lig]itnin-Rods. We take 

 from the Journal of the 'Jilt graph a few 

 valuable observations on the subject of 

 lightning-rods. The insulation of lightning- 

 rods, says the Journal, is a grave error, be- 

 cause the insulators to some extent arrest 

 the flow of currents of rarefied electricity, 

 which it is the true function of the light- 

 ning-rod to facilitate. On the other hand, 

 the insulator amounts to nothing as a bar- 

 rier against a discharge of lightning, which 

 can either pass through it or leap the short 

 distance between the rod and the building. 

 The prejudice in favor of insulators arises 

 from a misapprehension. Strictly speaking, 

 there are no non-conductors ; but that term 

 is applied to substances which conduct very 

 imperfectly and are subjected to violent 

 disruptive effects when a shock of electricity 



passes through them. To prevent a dis- 

 charge from leaving the rod and passing 

 through the building, something more must 

 be done than to attempt to keep it out by 

 erecting such flimsy and insignificant bar 

 riers as insulators. The rod must be ar 

 ranged so as to present points for the re- 

 ception and discharge of electricity at the 

 extremities of the building, both above and 

 below, and the different terminations in the 

 ground must be connected by rods lying 

 across the roof, so that lightning can be 

 provided with a path in an horizontal direc- 

 tion, which, being continuous, will be pre- 

 ferred to any series of detached masses of 

 conducting matter contained within the 

 building. 



Action of Absinthe and Alcohol. In an 



essay which received a prize from the French 

 Academy of Sciences last December, Dr. 

 Magnan states as follows the comparative 

 action of absinthe and of alcohol: Whether 

 injected into the stomach, pulmonary pas- 

 sages, cellular tissue, or vascular system, 

 these two agents produce different effects. 

 Essence of absinthe, in weak doses, causes 

 vertigo and sudden contractions in the mus- 

 cles of the anterior portion of the body ; in 

 strong doses, epileptic attacks and mental 

 disorder. The well-known effects of alcohol 

 are muscular debility, staggering, relaxation 

 of the limbs, and finally comatose sleep, 

 without any epileptic symptoms. Injected 

 simultaneously, alcohol and absinthe, instead 

 of neutralizing, intensify one another, and 

 the absinthine phenomena are in part masked 

 under the alcoholic. The substances used 

 in the manufacture of the liqueur absinthe^ 

 viz., the essences of anise-seed, angelica, 

 sweet-flag, marjoram, fennel, mint, possess 

 no toxic action. Hence all the injurious 

 effects of the liqueur are due purely to the 

 wormwood. Epileptiform symptoms never 

 follow from the use of alcohol, and they 

 are characteristic of absinthe. 



Fish-Life and the Pollution of Rivers. 



The injurious effects on fish of the pollution 

 of rivers with the refuse of gas-works have 

 been very thoroughly investigated by Prof. 

 A. Wagner, of Munich, and from his report 

 on the subject we take the following account 

 of some of his experiments. His method 



