May 1, 1896.] 



SCIENCE. 



675 



acter of recent work on these compounds and 

 the apparent ignorance of published results, 

 and a plea is made for greater care and accu- 

 racy in the preparation and analyses of these 

 salts. 



On the Quantitative Determination of Hydrogen 



by Means of Palladous Chloride. By E. D. 



Campbell and E. B. Haet. 



The hydrogen contained in a gas mixture can 



be completely absorbed by a 1 per cent, solution 



of palladous chloride, and determined more 



easily that way than by explosion with oxygen. 



On the Behavior of Certain Derivatives of Benzol 

 Containing Halogens. By C. Loeing Jackson 

 and S. Calveet. 



The presence of certain groups in a substi- 

 tuted benzine, containing also a halogen, makes 

 the halogen more easily replaceable. The effect 

 of the nitro group has been carefully studied, 

 and in this paper the authors give the results of 

 the influence of halogens on halogens, accord- 

 ing to their number and position in the molecule. 



The Cis and Trans Modifications of Benzine Hexa- 

 bromide. By W. R. Oendoeff and V. A. 



HOWELLS. 



The authors have made the cis modification 

 of benzine hexabromide, and give the results of 

 the chemical and crystallographic study of the 

 substance. 



suicide of Calcium. By G. DeChalmot. 



When lime, carbon and silica in excess are 

 heated in an electric furnace, a substance of 

 metallic appearance is formed. This is mainly 

 silicide of calcium, with a little carbide of cal- 

 cium and iron. 



The Conductivity of Yhtium Sulphate. By H. C. 



Jones and C. R. Allen. 



The conducting of different dilutions are 

 given in this paper. 

 The Practical Use in the Chemical Laboratory of 



the Electric Arc Obtained from the low Potential 



Alternating Current. By M. S. Walkee. 



The author advises the use of the electric arc 

 in the laboratory as a partial substitute for the 

 blo'wpipe, to show the effects of high tempera- 

 tures on refractory substances, and for the syn- 

 thetical preparation of some compounds of car- 

 bon. 



The Preparation of Allylerle and the Action of 

 Magnesium on Organic Compounds. By E. H. 

 Keiser. 



When acetone is conducted over hot magne- 

 sium a black powder is formed, which decom- 

 poses when brought in contact with water. The 

 product consisting of hydrogen and allylene is 

 passed through an ammoniacal solution of silver 

 nitrate, when an insoluble silver allylide is 

 formed. The copper and mercury compounds 

 have also been made. 



The Action of Urea and Sulphocarbanilide on Cer- 

 tain Acid Anhydrides. By F. L. Dunlap. 

 The formation of a number of complex com- 

 pounds can be explained on the supposition that 

 the reaction takes place in two stages, and the 

 author has isolated some of the intermediate 

 products. 



There is also a review of the work on Elehtro- 

 chemie, by W. Ostwald, and a note on Hie Di- 

 lution Law of Ostivald. J. Elliott Gilpin. 



THE journal op COMPARATIVE NEUROLOGY, 

 MARCH. 



Illustrations of Central Atrophy After Eye In- 

 juries. By C. iv. Hereick. 

 This brief article is a commentary on a plate 

 of drawings made from two series sections of 

 the brains of rabbits whose eyes had been ex- 

 tirpated shortly after birth and which had been 

 killed respectively 67 and 91 days after the op- 

 eration. 



Lecture Notes on Attention. An Illustration of the 

 Employment of Neurological Analogies for Psy- 

 chical Problems. By C. L. Herrick. 

 Experiments are adduced which go to show 

 that external attention is of the nature of a re- 

 flex which may or may not retain a relation of 

 subordinated connection with conscious pro- 

 cesses. Which particular impression may be 

 selected out of a given sense complex for 

 especial attention will depend upon habit 

 mainly. All of the impressions of a given field 

 of sense may become the content of that sense 

 and so may exert their appropriate effects in 

 infra-conscious spheres of association, etc. , even 

 though only part of them ever reach conscious- 

 ness. The discussion as to the possible number 

 of contemporaneous sensations is based on a 



