SCIENCE. 



So the sodium was not displaced or repelled under the 

 influence of the magnet, as it would have been had it 

 heen a conductor of electricity. 



There has been considered the possibility that metallic 

 particles thrown off from the electrodes might be the 

 conductors of the current. To determine if this were the 

 case, Mr. Goldstein made use of a tube with platinum 

 electrodes, in which the light from the kathode was de- 

 flected by a second kathode. The light alone underwent 

 this deflection, while the minute particles torn off from 

 the platinum, which lodged on the opposite wall of the 

 tube and formed a sort of mirror there, went exactly to 

 the same point after the deflection ot the light, as before. 

 There was thus no connection between the light of dis- 

 charge and the abraded metallic particles. 



But the most elegant demonstration in this matter has 

 been furnished by the experiments of De La Rue and 

 Mtiller : they arranged that the discharge of 2,400 chloride 

 of silver cells should pass through a circuit consisting of 

 a vacuum tube and a large variable resistance, A' — ; now 

 with different resistances R x , Ri, the resistance of 

 the vacuum tube formed a varying fraction of the whole 

 resistance ; and, according to Ohm's law for the fall of 

 potential along a conductor, the fall of potential along 

 the vacuum tube should have been variable, had its 

 function been that of a conductor. It was found in fact, 

 however, that the fall of potential along the tube re- 

 mained constant, no matter what resistance was intro- 

 duced in the remaining part of the circuit between the 

 poles of the battery, showing that the discharge was not 

 a case of true conduction, but that even at the lowest 

 pressure it was disruptive. 



THE AMERICAN CHEMICAL SOCIETY. 



The February meeting of the American Chemical 

 Society was held on Friday evening, the 3d inst. 



Dr. Orazio Lugo was elected a regular member. 



The first paper of the evening was " On Crystallized 

 Anhydrous Grape Sugar," by Dr. Arno Behr. 



It was customary in the preparation of the anhydrous 

 grape sugar to crystallize it out from an alcoholic solution, 

 particularly from that of methylic alcohol, but Dr. Behr was 

 lead to believe it possible that a simpler method could be 

 devised. After some experimenting, he found that it 

 could be obtained from the ordinary hydrated solution. 

 A solution with 12 to 15 per cent of water gave the best 

 results. In the description of its properties, Dr. Behr 

 stated that when dried in a current of dry air, the crys- 

 tallized sugar would not retain more than two or three 

 per cent moisture, its reaction was neutral, its melting 

 point is between 141° and 145 C. When tested by the 

 polariscope it showed birotation. Dr. Behr then briefly 

 referred to its economic uses, how by its cheapness it 

 would be largely used by the confectioner, the druggist, 

 and by those who manufacture wines. He also stated 

 that as regards its sweetening qualities, instead 

 of requiring twice as much or more to make it equal 

 to cane sugar, he had found that one and two-thirds 

 as much was sufficient. Mr. Nelson H. Darton followed 

 with a short paper " On the Precipitation of Tannic Acid 

 as Tannate of Copper." This paper was a supplementary 

 description of Mr. Darton's method, already read before 

 the Society. It consists in the precipitation of tannic 

 acid by the ammonia sulphate of copper. The precipi- 

 tate was tested for ammonia with negative results, and 

 therefore it was contended by Mr. Darton that the pre- 

 cipitate was composed of copper tannate and not the 

 double salt as has been elsewhere claimed. 



The final paper of the evening was by Dr. E. Waller, 

 of the School of Mines, Chemist to the New York Board 

 of Health. Its title was " On the Water Supply of New 

 York City. The object of this paper was to contradict 

 certain statements made by Prof. Leeds in his recent 

 paper read before the Society and also published in the 



Chemical A T e?us. Dr. Waller produced the analysis 

 made by Dr. Booth in (843, then by Dr. Chilton running 

 between the years 1843 and 1859, Dr. Chandler's results 

 from analysis in 1869-72, and finally his own, which have 

 been regularly reported since 1872. These latter were 

 represented by means of curved lines on diagrams which 

 showed exactly the amount of each constituent for any 

 time during the past nine years. These we may con- 

 dense and show by the following table : 



PARTS IN IOO.OOO. 



Mineral matter 



Org. and vol. matter 



Total solids 



Hardness . 



Oxygen by permanganate method 



Maximum. Minimum. Average. 



8.44 3.20 5,702 



4.40 I.67 004 



11.07 4- 8 ° 7-3 8 



5.40 1.88 3.21 



0.383 0.047 0.180 



The results ohtained by Prof. Leeds in comparison 

 with those showed from the above table were in several 

 instances quite different. Thus, Prof. Leeds finds the 

 total solids to be higher than any result obtained by the 

 New York Board of Health during the past fourteen 

 years. In other determinations similar discrepances 

 were shown by Dr. Waller. The statement that the Croton 

 water was contaminated by tanneries and other factories 

 was objected to as incorrect, the tanning having long 

 since ceased on account of the scarcity of trees. A state- 

 ment from the Chief Engineer of the Water Department 

 was read, in which he claimed that the water shed of the 

 Croton River was the cleanest of any from which the 

 supply of drinking water was obtained, either in this 

 country or abroad. The population of the country 

 through which the Croton flows does not exceed 20,000 

 inhabitants, or about one person to every ten acres. In 

 comparison with other cities, the number of inhabitants 

 to the square mile residing along the water shed of 

 Croton, was stated to be extremely small, thus : 



Population 



to the 

 Square Mile 



270 



229 



"9 



London . 

 Boston . . 

 Brooklyn 

 Schnectady 

 Cohoes 

 West Troy 



New York 



Rochester 



Albany 



Poughkeepsie, supply from Hudson River 



rawing their supply from 

 the Mohawk River. 



103 



6S 

 36 

 77 

 86 



By arguments such as the above, Dr. Waller maintained 

 that the conclusions reached by Professor Leeds were 

 erroneous. In the discussion that followed certain of 

 Dr. Waller's modes of analysis were criticized by Dr. 

 Endemann, but his remarks were merely on a side issue, 

 and had no bearing on the results. M. B. 



To the Editor of "SCIENCE." 



Dear Sir : — I am sorry to find that I have been mis- 

 led as to one important fact stated in my paper upon 

 Standard Time which appeared in *' Science " tor Janu- 

 ary 2 1 st. The Signal Service has not applied for an appro- 

 priation of $25,000 for the purpose indicated in the paper, 

 but a bill introduced in the house by Mr. King of Louisi- 

 ana, asks this amount to enable the Naval Observatory 

 to establish and drop time-balls at the principal ports of 

 entry ; and this was confounded with the Signal Service 

 bill in the mind of my informant. 



I supposed I had good authority for what I wrote, but 

 as the result shows 1 ought to have looked into the mat- 

 ter more closely before trusting the statement to type. I 

 regret exceedingly to have aided in giving currency to an 

 erroneous statement. 



C. A. Young. 



Princeton. 



