ii6 



SCIENCE. 



[Vol. XXII. No. 552 



coming impervious during use, a granular material was 

 obtained by powdering plaster figures, igniting and pass- 

 ing through a 2 mm. sieve. The substance was air-di-ied 

 and ordinary ether used. Anhydrous ether apparently 

 did not affect the results, though these were lowered by 

 a previous drying of the food stuff. The extracts, though 

 pure, were not constant in weight. Spanish earth was 

 found to yield satisfactory results after the following pro- 

 cedure. The fine powder was mixed with water, sufficient 

 sulphuric acid added to remove the carbonates, and the 

 whole evaporated to dryness and ignited. The mineral 

 was then powdered and passed through a 2 mm. sieve. 

 A cotton plug is inserted in the end of the extraction 

 tube, and upon this a layer of 3-4 cm. of Spanish earth, 

 after which a mixture of the earth and fodder and then 

 another plug. 12-15 grammes of the earth were used for 

 5 grammes of the fodder. With ordinary fodders the re- 

 sults were the same whether hydrous or anhydrous ether 

 was employed, but with foods rich in fat lower results by 

 a few tenths were obtained with the anhydrous. A pre- 

 vious drying of the substance, when Spanish earth is used, 

 fives low results, probably due to the retention of that 

 portion of the fat which may have been changed by the 

 action of the heat. 



Synthesis of Purpureo-and Luteo-Chromium Chlorides. 



Professor Christensen, of Copenhagen, has produced by 

 direct synthesis the so-called purpureo-and luteo-chro- 

 mium chlorides, Cr CL 5 NH3 and Cr CI3 6 NH,. A small 

 quantity of violet chromium chloride, dried at 100°, * is 

 X^laced in a beaker and immersed in a freezing mixture of 

 solid carbon dioxide and ether. Liquid ammonia (NH-) 

 is slowly added. At this temperature no reaction takes 

 place, but upon removing from the freezing mixture and 

 warming to — 38.5°, the boiling point of ammonia, a sud- 

 den reaction sets in, converting the chloride into a red 

 mass, consisting largely of the xaurpureo-chloride. The 

 excess of NH, is eliminated as gas. The product is 

 washed with cold water and hydrochloric acid, finally dis- 

 solved in water and the solution dropped into concen- 

 trated hydrochloric, in which the purpureo-chloride is 

 insoluble, when the red crystals of the pure salt are 

 thrown down. The first aqueous washings are yellow and 

 yield a yellow crystalline precipitate of luteo-nitrate upon 

 the addition of concentrated nitric acid. The reaction 

 takes place between very narrow limits — immediately 

 above and below the boiling point of ammonia — 38.5°. 

 Determination of Germanium. 



Quantitative estimations of the rare metals being un- 

 known to text-books on chemistry, the methods adopted 

 by experienced analysts have a decided instructive value. 

 The following is the procedure in an analysis of the new 

 mineral canfieldite as given by Mr. S. L. Penfield in the 

 Am. Jour, of Science. A preliminary qualitative examina- 

 tion was made showing the mineral to be essentially a 

 sulpho salt of germanium and silver. The silver and sul- 

 phur were determined as usual. For the germanium, 2 

 grammes are oxidized with nitric acid, a little sulphuric 

 being added and the excess of nitric removed by evapora- 

 tion to dryness. The residue is dissolved in water, which 

 has been rendered slightly acid, if necessary, and the sil- 

 ver precipitated with ammonium thiocyanate, filtered and 

 the filtrate containing the germanium collected. The 

 solution is evaporated to dryness in a platinum dish with- 

 out danger, no acid being present to form with the ger- 

 manium a volatile compound. The excess of sulphuric 

 acid is driven off by heat, and the ammonium thiocyanate 

 is destroyed by the nitric acid piresent. The residue is 

 covered with a little strong ammonia (NH^OH) into 

 which sulphuretted hydrogen is conducted, thus dissolv- 



Centigrade un- 



ing the germanium oxide and leaving all heavy metals, 

 except those which form sulpho salts soluble in am- 

 monium sulphide, undissolved. The filtrate from this 

 solution is collected in a platinum crucible and evap- 

 orated on a water bath, the residue oxidized by concen- 

 trated nitric, and the excess of the latter removed by a 

 second evaporation. The mass in the crucible is now 

 gently ignited and weighed, the germanium being de- 

 termined as the oxide, GeO^. There is no loss of weight 

 on subseqirent heating to a red heat. 



Another scheme by which all of the determinations are 

 made in one sample is briefly as follows: Solution in 

 nitric; precipitation of the silver by means of hydrochloric; 

 precipitation of the sulphur with barium nitrate; removal 

 of the excess of chlorine and barium, in one op)eration, 

 with silver nitrate and sulphuric acid; removal of the sil- 

 ver by means of ammonium thiocj'anate; and the final de- 

 termination of the germanium as above. 



THE WORLD'S CONGEESS AUXILIARY OF THE 

 COLUMBIAN EXPOSITION. 



BY GEO. H. JOHNSON, SO. D., ST. LOUIS, MO. 



One of the greatest attractions of the Columbian Expo- 

 sition is outside of the exposition. In the World's Con- 

 gresses we have an exhibit of the world's intellectual 

 progress and present condition such as has never been 

 attempted before. For the first systematic attempt to 

 make such a comprehensive exhibit of the world's thought 

 by spoken language only the congresses have been very 

 successful. During the whole of the six months that the 

 fair is open the Memorial Art Palace, foot of Adams 

 Street, Chicago, is the place of assembly for those who are 

 prominent in any branch of theoretical and practical 

 learning. At the fair we see the magnificent v/ork of 

 great masters. At the Art Palace we see the great mas- 

 ters themselves. As the creator is greater than his work, 

 as thought is greater than action, so are the world's con- 

 gresses greater than the fair. 



It has been said that President Bonney, since the first 

 day of May, has done nothing but open congresses; and 

 indeed, that is quite sufficient to keep him busy, since 

 several congresses meet each week, and each one is 

 opened by Mr. Bonney with felicitous remarks apjpropri- 

 ate to the subject. 



Little effort, apparently, has been made here to show 

 the intimate relations which exist between different de- 

 partments of science and art. To attend one congress 

 and then another exhibits as complete a change as to pass 

 from Machinery Hall to the Fine Arts Building. Since 

 the congresses are designedly meetings for sj)ecialists, it 

 is to be expected that very few can take a prominent jjart 

 in more than one congress. But the wisdom of such a 

 complete separation between dependent and cognate sub- 

 jects as some of the programs show, is open to question. 

 For example, the Congress on Higher Education did not 

 consider University Extension because the latter subject 

 was considered exclusively in its own congress. The en- 

 gineering educators coulcl not attend any of the meetings 

 of the civil, mechanical, naval, mining, metallurgical, or 

 military engineers without leaving their own meeting, 

 since all these and others were in session simultaneously. 



Perhaps the greatest need of cooperation between 

 closely related specialists was shown in the congresses on 

 experimental and rational psychology. These meetings 

 were held simultaneously in opposite halls of the insti- 

 tute, and each succeeded remarkablj' well in ignoring the 

 work of their opjDosite brethren. Indeed, it might have 

 been inferred from some of the remarks that what is ex- 

 perimental is not rational, and what is rational will not 

 bear the test of experiment. A professor in one famous 



