CHEMISTRY. 



149 



In Knoblauch's improved form of apparatus 

 fur the determination of sulphur in cow-gas, ;t 

 metallic holder is filled with gas, and water i* 

 turned on. The gas, together with five or six 

 times its volume of air, is drawn into a com- 

 bustion tube and over heated asbestos. The 

 sulphur products are absorbed in a solution of 

 -aim carbonate. 



Improvements in apparatus for rapid gas 

 analysis by Dr. Arthur H. Elliott corisist in 

 reducing the length of the tubes by enlarging 

 the upper portion of the bulbs, and by substi- 

 tuting a solution of bromine in potassic bromide 

 for the liquid element to absorb illuminants. 



For the generation of sulphureted hydrogen 

 or hydrogen gas, J. H. J. Dagger uses a glass 

 vessel containing hydrochloric acid, which is 

 connected from its lower tubulure, by means of 

 a flexible tube, with the generator, and the two 

 vessel?, supported by wooden forks, are ar- 

 ranged at different heights and fixed to the 

 side of the H 2 S cupboard. The lower part of 

 the generator is filled to about half an inch 

 above the end of the acid-tube with pieces of 

 glass or glass marbles; above this layer is the 

 iron sulphide or the zinc, as the case may be. 

 in small pieces. The flow of gas can be stopped 

 or regulated by altering the levels. 



An adjustment of the Reichard's aspirator has 

 been applied by Prof. LeR. C. Cooley as part 

 of an apparatus for removing noxious vapors 

 in the evaporation of corrosive liquids. 



To obviate the liability to accident from the 

 bumping that follows an explosion in Liebig's 

 trough, Arthur Michael places an India-rubber 

 plug on the bottom of the trough, and holds 

 the eudiometer firmly down upon it. 



An apparatus has been devised by Thomas 

 C. Van Xuys for the estimation of carbonic 

 acid by means of barium hydrate, the chief 

 purpose of which is to afford means for pre- 

 venting the contact of external air containing 

 carbonic acid with the barium hydrate when 

 triturated with oxalic acid or when filtered and 

 washed. 



Mr. Fletcher, of Warrington, has introduced 

 a tubing made of two layers of India-rubber 

 with soft tin-foil vulcanized between, which is 

 said to be gas-tight under any pressure, and 

 free from smell after long-continued use, while 

 it retains the flexibility and elasticity of an or- 

 dinary rubber tube. 



Xickel has been found by Prof. Dittmar to 

 be a most durable material for making basins 

 in which to conduct operations with aqueous 

 caustic alkalies. 



In an apparatus described by G. H. Bailey 

 for maintaining constant temperatures up to 

 500 C.. the substance to be heated is placed 

 in a glass tube, together with the bulb of an 

 air-thermometer, and these are inclosed in a 

 wider tube resting on the iron casing of a fur- 

 nace. The air-thermometer serves to measure 

 the temperature, and is connected with a gas- 

 regulator, by which means the temperature 

 may be kept constant at any desired degree. 



A source of error in experiments, due to the 

 formation of carbonic dioxide by the action of 

 ozone on the cork stoppers, and India-rubber 

 connectors of the apparatus, has been detected 

 by Kieser and F. H. Storer, of Bu-sey Institute. 

 H. Karsten had also observed that such con- 

 nectors are liable to oxidation, even in mere 

 air and at ordinary temperatures. He found 

 the yield of carbonic acid increased fourfold 

 when non-nitrogenized substances were ex- 

 posed to air ozonized by phosphorus instead of 

 to ordinary atmospheric air. 



Miscellaneous. The address of Prof. Tilden, as 

 vice-president for 1888 of the chemical section 

 of the British Association, was devoted largely 

 to the subject of chemistry teaching, which, in 

 spite of the great advance of the science, was 

 still hampered, he said, by the ignorance and in- 

 difference of the public. One man is required 

 to teach college classes, both elementary and 

 advanced, in pure and applied chemistry, inor- 

 ganic and organic, theoretical and practical. 

 " This is a kind of thing which kills specialism. 

 and without specialists we can have not only 

 no advance, but no efficient teaching of more 

 than rudiment*. That teachers ought to en- 

 gage in research at all is by no means clear to 

 the public and to those representatives of the 

 public who are charged with the administration 

 of the new institutions. ... A popular mis- 

 take consists in regarding a professor as a liv- 

 ing embodiment of science complete, infallible, 

 mysterious ; whereas in truth he is, or ought 

 to be, only a senior student who devotes the 

 greater part of his time to extending and con- 

 solidating his own knowledge for the benefit 

 of those who come to learn of him, not only 

 what lies within the boundaries of the known, 

 but how to penetrate into the far greater region 

 of the unknown. Moreover, the man who has 

 no intellectual independence, and simply ac- 

 cepts other people's views without challenge, 

 is pretty certain to make the stock of knowl- 

 edge with which he sets out in life do service 

 to the end." The little demand among school- 

 masters for high attainments in chemistry, the 

 indifference of manufacturers who, when they 

 want chemical assistance, instead of employing 

 trained chemists are often satisfied with the 

 services of boys " who have been to an evening 

 class for a year or two," and the difficulty of 

 finding a satisfactory career in connection with 

 chemistry, are assigned as other reasons for the 

 lack of attention to the efficient teaching of 

 the science. The disposition to encourage 

 young chemists to engage in investigation and 

 attack difficult problems, may be carried too 

 far. " Already we are in danger of losing the 

 art of accurate analysis. One constantly meets 

 with young chemists who are ready enough to 

 onstitution of benzine, but can not 

 make a reliable combustion. And, according 

 to my own experience, attempts at research 

 among inexperienced chemists become abortive 

 more frequently in consequence of deficient 

 analytical skill than from any other cause." 



