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THE POPULAR SCIENCE MONTHLY 



seeds had become attached to the core 

 when under water, and had afterward ger- 

 minated when the core was stored. 



Prof. Brudenell Carter, in an address 

 on the "Relations of Ophthalmology to 

 General Surgery," takes the ground that, 

 while the growth of specialism in this de- 

 partment has given us improved operations 

 and more dexterous operators, it has re- 

 tarded investigation by diminishing the 

 number of laborers in the field, and the 

 opportunities of those laborers to study 

 the facts from the standpoint of general 

 pathology. 



An Italian chemist, A. Casali, obtains a 

 green pigment by calcining an intimate 

 mixture of one part of bichromate of potash 

 and three parts of baked gypsum, of the 

 variety known as scagliola. The result is 

 a grass-green mass which, on boiling with 

 water, or mixing with dilute hydrochloric 

 acid, leaves a fine powder of an intense 

 green. 



Reichardt recommends the use of the 

 microscope in determining the mineral con- 

 tents of potable water. On evaporating a 

 few drops on a plate of glass, it is easy to 

 distinguish carbonate and sulphate of lime 

 and of magnesia, chloride of sodium, and 

 nitrate of potash and of soda. C. Bischof 

 further recommends the use of the same 

 instrument for determining the organic sub- 

 stances contained in water. 



A scheme has been recently devised for 

 supplying Loudon with au inflammable mixt- 

 ure of gases to replace coal. The new gas, 

 " pyrogen," as it is called, is a mixture of 

 nitrogen and carbonic oxide, three-fourths 

 by weight consisting of the latter gas. The 

 combustion temperature of pyrogen is stated 

 to be 2,700 Cent., and for heating-purposes 

 the flame of the burning gas is to be allowed 

 to raise some good radiating substance to 

 incandesence in an ordinary grate. 



Felizet, of Elbeuf, having observed that 

 in epidemics of foot-and-mouth disease no 

 beast affected with cow-pox is ever stricken 

 with the former disorder, vaccinated thirty 

 oxen, and not one of the twenty-five beasts 

 effectually vaccinated showed any sign of 

 foot-and-mouth disease, even after living for 

 months among animals largely affected with 

 it. 



Prof. Stanley Jf.vons is opposed to 

 the project of assimilating the American 

 dollar to the English pound sterling; he 

 advocates, rather, assimilation to the five- 

 franc piece. The partial accession of the 

 United States to the franc system would, 

 he says, immensely increase the motives for 

 the English to accept it also, thus prepar- 

 ing the way for an international coinage. 



For the purpose of photographing solar 

 eclipses, Mr. Brothers, of the Royal Astro- 

 nomical Society of London, suggests that at 

 least three achromatic lenses of five or six 

 feet focal length, corrected for the actinic 

 rays, should be coustructed, with all suita- 

 ble apparatus, to be in readiness for use 

 when required. The light of the corona, he 

 adds, is sufficiently actinic to produce good 

 pictures when an instrument of long focus 

 is used it is only a question of time in the 

 exposure and accuracy in the adjustment 

 of the driving-clock apparatus attached to 

 the equatorial mounting. 



The cruelty-to-animals bill, now under 

 consideration in the British Parliament, 

 provides that vivisection should only be 

 performed with a view to the advancement 

 of human knowledge, the prolongation of 

 human life, or the alleviation of human suf- 

 fering ; that it must take place in a regis- 

 tered laboratory ; that it must be performed 

 by a person duly licensed ; that the animals 

 must be put under the influence of anaes- 

 thetics ; and that, where pain would be pro- 

 longed after the anaesthetic effects had sub- 

 sided, the animals should be killed. 



In their last report, the Commissioners 

 in Lunacy in England discourage the prac- 

 tice, which has grown to be quite general, 

 of filling up the asylums with idiots, imbe- 

 ciles, and eccentric or troublesome paupers, 

 to the exclusion of the really insane, who 

 need and are entitled to the skill, care, and 

 attention, that asylums are intended to af- 

 ford. 



The Commission Superieure of the Paris 

 Exposition of 1878 has decided upon the 

 general plan of the enterprise, and esti- 

 mated the probable receipts. The expense 

 is set down at 35,000,000 francs, and the 

 receipts at 19,000,000; difference, 16,000,- 

 000 francs. To meet this deficit, the city 

 of Paris will contribute 6,000,000 francs, 

 and the state 10,000,000 francs. The 

 buildings for the exposition will be erected 

 in the Champ de Mars and in the Troca- 

 dero localities situated on opposite banks 

 of the river Seine. At first, it was proposed 

 to widen temporarily the bridge known as 

 Pont d'lena, but soon another project was 

 entertained that of erecting a new bridge 

 forty metres in width. The question is yet 

 under deliberation. 



In the petroleum-mines of Alsace the 

 miners test their safety-lamps in the follow- 

 ing manner before going down the pits : At 

 the bottom of an open jar is placed a small 

 quantity of petroleum-spirit, the vapor of 

 which, mingling with the air in the jar, 

 forms an explosive mixture. The lamp is 

 plunged into this mixture, and the slightest, 

 defect in the lamp is proved by an explosion. 



