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SCIENCE 



[N. S. Vol. LII. No. 1357 



highest water occurs a few miles to the right 

 and at about the time of passage of the center 

 and high water is observed from 100 to 200 

 miles to the right of the storm, while to the 

 left it is hardly observed at all. 



An interesting point is the eSect upon the 

 height of the water which may be attributed 

 to the decreased atmospheric pressiu-e in the 

 center of the storm. This of course will allow 

 the water to be raised in that vicinity. In the 

 great hurricane of 1900, which passed inland 

 at Galveston the pressure was low enough to 

 have caused a rise of 1.5 feet in the level of 

 the water. There is no danger of confusing 

 such an eilect as this, however, with the main 

 storm-tide, because the amplitude of the 

 storm-tide is much greater; indeed, in this 

 case, it was 15 feet. 



The apparent simplicity of this method of 

 forecasting hurricanes must not be overesti- 

 mated, however. The hurricane is a capri- 

 cious disturbance and difficulties may be in- 

 troduced by its unusual conduct either with 

 respect to its rate of movement, or point of re- 

 curving. An example of this may be made 

 in the hurricane of September 21-22, 1920.^ 

 This storm, as indicated by the tides after it 

 entered the Gulf, was moving in the direction 

 of the coast between Corpus Christi and Gal- 

 veston; but it recurved and with imespected 

 speed swept northward and inland near Mor- 

 gan City, La. The difficulty was that, owing 

 to the unexpected late recurving and unusual 

 speed, it was impossible to forecast the actual 

 point of entrance. As a consequence, the 

 warnings were displayed first from Corpus 

 Christi to Port Arthur, Texas, and then ex- 

 tended to include the coast as far east as 

 Pensacola. In retrospect, it is seen that the 

 method worked out well enough; but the 

 peculiarities of the storm's movement preclude 

 a satisfactory application of the method. In 

 this case, the method did not give as great 

 precision as might be required; but it must 

 not be inferred that the method is faulty. 



2C/. Cline, Isaac M., "The Life History of 

 Tropical Storm in Louisiana, September 21 and 

 22, 1920," Monthly Weather Beview, September, 

 1920, pp. 520-524. 



Anything that will improve the forecasting of 

 hurricanes is welcomed, and it can not be said 

 that Dr. Cline's paper does not constitute a 

 genuine contribution to this difficult and 

 troublesome question. 



C. LeEoy Meisinger 

 Washington, D. C. 



SPECIAL ARTICLES 



THE COLLECTION OF RADIUM EMANATION 

 FOR THERAPEUTIC USEi 



The practise of using radium emanation 

 instead of radiimi salts for therapeutic pur- 

 poses is now thoroughly established in this 

 country. Its advantages are so patent that 

 all of the hospitals and clinics, where large 

 quantities of radium are employed, have had 

 their radium salts converted to soluble form, 

 and collect emanation from solution. 



It is necessary, however, to separate the 

 emanation from hydrogen, oxygen and other 

 gases which accompany it in the collection, 

 in order to reduce its volume to meet the re- 

 quirements. This can be accomplished by 

 several different methods: (1) The chemical 

 method of purification by heating copper 

 oxide and other chemicals in a tube through 

 which the gases pass before being confined 

 in small volume over mercury; (2) the nlethod 

 of Professor Duane^ of passing the gases over 

 an electrically heated partially oxidized cop- 

 per wire; (3) the method of freezing emana- 

 tion at liquid air temperature and pumping 

 off the residual gases. This method may also 

 be employed in conjunction with either of 

 the first two. 



All three methods require a rather com- 

 plicated apparatus and manipulations which 

 can be carried out only by a specialist. It 

 occurred to the writer that some simplifica- 

 tion might be introduced by collecting emana- 

 tion from the highly heated or fused radium 

 salts, thus avoiding the presence of water and 

 the consequent large volume of hydrogen and 

 oxygen resulting from its decomposition. It 



1 Published with permission of the director of 

 the United States Bureau of Mines. 

 2Phys. Bev. (2), 5, 311, 1915. 



