32 



OCEAN ATMOSPHERIC-ELECTRIC RESULTS 



Penetrating Radiation. — As previously reported, Dr 

 Kolh6rster delivered his penetrating radiation instru- 

 ment (Gunther and Tegetmeyer No. 5503) in Hamburg 

 and, as will be seen from the records transmitted, daily 

 intercomparisons between this instrument and penetrat- 

 ing radiation apparatus 1 have been made. There are 

 some difficulties in the use of an instrument of this 

 type, rigidly mounted on a rolling ship, and having 

 coarse fibers widely separated which are in constant 

 and irregular motion. It is necessary to use a large 

 initial potential (over 300 volts), and the time interval 

 for each observation must be at least one hour. It would 

 be an advantage to have the initial voltage the same for 

 each observation, no doubt, but with the magnetic con- 

 tact-device now in use, it has been found impossible so 

 far to reproduce a deflection with the same number of 

 cells. The "zero" position of the fibers has moved 

 about 15 divisions (full scale deflection is about 160 di- 

 visions) to one side of the center and there seems no 

 ready way of bringing it back to the center. For the 

 computation of the values of R the calibration curve sup- 

 plied by Dr. Kolhorster has been used, but with the 

 change of zero it is doubtful whether it still holds. It is 

 intended to recalibrate the instrument before leaving 

 Reykjavik. 



Potential-Gradient Apparatus 2. --During the damp 

 weather encountered since leaving Hamburg, trouble has 

 been experienced with the sulphur insulators supporting 

 the collector-system, and since arriving at Reykjavik 

 these have been recast. It would be a convenience if one 

 or two spare sets of these insulators, with the screw 

 holes made, could be supplied, as it is impossible to re- 

 cast the sulphur while the ship is in motion and dry in- 

 sulators could be mounted easily when necessary. The 

 shield protecting the hard rubber connection of the han- 

 dle of the umbrella- shaped conductor or collector was 

 accidentally dropped overboard and a replacement of 

 this is requested as soon as possible. Frequent neces- 

 sity for using the main engine has decreased the number 

 of opportunities for making potential-gradient observa- 

 tions. Reduction-factor observations on ship and shore, 

 using both recorders and eye-reading instruments have 

 been made at Reykjavik but the final analysis of the re- 

 sults has not been completed. 



Silver Chloride Batteries. --Some of the batteries 

 are beginning to show signs of rapid deterioration. 

 Number 14832 has had two replacements; no. 14689, 

 which had fifteen cells replaced during May, has had the 

 remaining eighty-five renewed; and no. 14870 needs en- 

 tire renewal. With the new penetrating radiation appa- 

 ratus, requiring 300 volts for its use, it seems neces- 

 sary that six entirely new batteries should be supplied 

 at Balboa. The 45-volt Burgess batteries can be used 

 for some purposes, of course, but they are not conveni- 

 ent where intermediate voltages are required. 



Acknowledgment is made of the memorandum of 

 July 7, 1928 dealing with the penetrating radiation meas- 

 urements. The comparison observations had been made 

 before receipt of this memorandum but the observations 

 follow closely along the lines suggested. Advantage wUl 

 be taken of any opportunity to make measurements on an 

 exposed part of the quarter-deck to determine the shield- 

 ing effect of the atmospheric-electric observatory, and 

 other parts of the ship's superstructure. Dr. Kolhorster 

 had informed us that the residual ionization of the cham- 

 ber of his instrument is equal to 1.3 ions per cc per sec. 

 It is intended to make diurnal-variation observations 



at least once per week from now on, of as many of the 

 atmospheric-electric elements as the weather permits. 



Co mment s 



Some Preliminary Deductions from Data up to July 

 19, 1928. --The penetrating radiation observations re- 

 ceived from the Carnegie thus far show characteristics 

 much like those obtained on previous cruises and the 

 comparisons between penetrating radiation apparatus 1 

 and Gunther and Tegetmeyer No. 5503 indicate that these 

 two instruments on the whole give consistent values. 

 The observations obtained July 19, 1928 are the only 

 ones seriously out of harmony with the general trend. 



A rough estimate from these data of the ratio of 

 Eve's constant for penetrating radiation apparatus 1 to 

 that for Gunther and Tegetmeyer No. 5503, gives 0.9 + 

 0.1, and the residual ionization for penetrating radiation 

 apparatus 1, taking that for Gunther and Tegetmeyer No. 

 5503 as 1.3 ions per cc per sec as given by Kolhorster, 

 is 1.9 t 0.1 ions per cc per sec. This last is surpris- 

 ingly close to that estimated by Mauchly.^ These values 

 are only tentative; the final values must be deduced by a 

 statistical study of a more extensive mass of data. 



Using the value for Eve's constant determined at 

 Newport News (namely 5. Ox 109) and assuming the square 

 law for recombination, we find that the mean number of 

 ions in a cc of air during the period July 9 to 19 is by cal- 

 culation 725, whereas the mean of observations is 547. 

 Although the calculated value is about 30 per cent too 

 great, it is considerably closer than other calculations 

 in which the present controls are lacking. The discrep- 

 ancy here maybe in part because the value of Eve's con- 

 stant is too small since the effect of masts, rigging, etc., 

 is not included, and in part because nuclei increase the 

 rate of recombination and thus reduce the total number 

 to be found at any time. An estimate of the former fac- 

 tor can be obtained by the method indicated under "Com- 

 parative measurements" of penetrating radiation (p. 14) 

 and a control for the latter may be derived from nuclei- 

 count observations. 



The Desirability of Simultaneous Nuclei Count. Ion 

 Count, and Penetrating Radiation Observations probably 

 has not been stressed sufficiently heretofore. These 

 three elements are needed to determine definitely 

 whether the penetrating radiation is the sole and ade- 

 quate ion-producing agent over the oceans. This is one 

 of the most important unsolved problems in atmospheric 

 electricity. 



The Difficulties with Gunther and Tegetmeyer Rad- 

 iation Apparatus No. 5503 which were mentioned in the 

 observer's report probably will necessitate opening the 

 chamber in order to examine and adjust the troublesome 

 parts. If the defects are such that this instrument is not 

 usable, it should be opened and the attempt made to ad- 

 just the contact finger so that it makes more positive 

 contact. The electrometer element should be examined 

 also to ascertain the cause of the zero shift and erratic 

 behavior reported and should be adjusted if possible. If 

 satisfactory adjustment is obtained, the chamber should 

 be sealed again and used as before. Possibly the points 

 at which the quartz support is attached to metal may be 

 the real source of difficulty as the cement may have 

 loosened or broken away. DeKhotinsky cement (possibly 



^Researches of the Department of Terrestrial Mag- 

 netism, vol. 5. 1926. 



