Chemistry and Physics. 59 



strength, and the filtrate is titrated directly in a bottle in the 

 presence of a little chloroform with potassium iodate solution 

 until the color of iodine, which is produced in the chloroform, at 

 last disappears. The reaction in the presence of the strong 

 hydrochloric acid proceeds according to the equation 



2SbCl 3 + KI0 3 4- 6HC1 = 2SbCl 5 4- KCl + IC1 4- 3ll 2 0. 

 Since tin, copper, and iron do not interfere with the method, it 

 is convenient in many cases, and it appears to give very accurate 

 results. — Jour. Indust. and Eng. Chem., iii, No. 4. h. l. w. 



6. The Radio-activity of the Dilrkheim Mineral Waters. — 

 Since it had been found by Ebler in an examination of the "Max- 

 quelle " water of Diirkheim that a certain amount of radio-activ- 

 ity appeared to follow the alkali-metals, and since on this account 

 it was suspected that a sixth alkali metal with radio-active prop- 

 erties might exist in this water, Eblek and Fellner, in connec- 

 tion with an elaborate investigation of the radio activity of these 

 waters and their products, have made a further study of the 

 question of the presence of a new alkali metal. The result, how- 

 ever, is disappointing from a chemical point of view, for they 

 found that potassium salts prepared from the water of this spring 

 showed no more radio-activity than ordinary potassium salts.— 

 Zeitschr. anorg. Chem., lxxii, 233. h. l. w. 



7. Bidletin of the Bureau of Standards. — The third number 

 of volume VII, recently issued, opens with a paper by L. W. 

 Austin, giving in detail the results of Some quantitative experi- 

 ments in long-distance radiotelegraphy. These tests were carried 

 on two years since under the auspices of the Navy Department 

 between two cruisers and the wireless station at Brant Rock. 

 Measurements were made up to a distance of one thousand miles, 

 their chief object being the determination of the law governing 

 variations of strength of signal with the distance. The results 

 arrived at, briefly stated, are as follows : 



"(a) Over salt water the electrical waves decrease in intensity 

 in proportion to the distance as found by Duddell and Taylor. In 

 addition they are subject to an absorption which varies with the 

 wave length and which may be expressed mathematically by the 



term e . The complete expression for the received current 



is then 



!„ = §.-*>. 



This is true in general for day transmission. The absorption at 

 night is entirely irregular, varying from zero to the day value, 

 but is on an average much less during the winter than in summer. 

 Variations also appear to occur during the daytime, but these are 

 probably in general small. 



" (b) The received antenna currents between two stations with 

 salt water between are proportional to the product of the heights 

 of the sending and receiving antennas and inversely proportional 



