REPORT ON ATMOSPHERIC ELECTRIC WORK 



35 



end, from the vertical strip to which it was held with 

 shellac. In view of the difficulty of making the neces- 

 sary repairs in a satisfactory manner on board ship, 

 the advisability of having dry air in the apparatus when 

 again assembled and sealed up, and of making some 

 changes mentioned below, it is recommended that the 

 instrument, with its accessories, be returned to Wash- 

 ington from Balboa. Tests made with the instrument 

 while it was open showed how easy it was for the con- 

 tactor arm to pass to the wrong side of the contact pin 

 and it is recommended that this pin be made longer and 

 also with an upper extension so that the contactor arm 

 cannot slide over it as perhaps it does now. Also, if 

 possible, the substance used for fastening the various 

 parts together, such as the contactor arm to the amber 

 insulator, should have a higher melting point. There 

 has been no means of telling the temperature inside the 

 chamber but the attached thermometer frequently reg- 

 isters 40° C, which is the limit of its scale. 



Silver Chloride Batteries. --It is planned to test all 

 cells here and make up as many complete batteries as 

 the stock of spare cells on hand will cover. It will be 

 necessary to purchase some Burgess batteries here. 



Comments 



Potential-Gradient Recorder. --The reduction fac- 

 tors obtained at Bridgetown for the potential -gradient 

 recorder are very consistent indeed. It was rather ex- 

 pected that the factors for "boom to port" and for 

 "boom to starboard" would differ more than was found, 

 but it was not surprising to learn that values for "main- 

 sail up" differed inappreciably from those obtainedwith 

 "mainsail down." Apparently no observations were 

 made with the boom over the crutch. Will it be possible 

 at all times to avoid that position when potential-gradi- 

 ent is l)eing recorded? 



Penetrating Radiation Apparatus No. 5503. - -The 

 description of defects in penetrating radiation apparatus 

 Giinther and Tegetmeyer 5503 as given by Mr. Parkin- 

 son has been helpful in determining the methods of re- 

 conditioning this apparatus. It is expected that this will 

 be repaired and tested in time to be placed again on the 

 Carneg ie at Callao. The duplicate instrument did not ar- 

 rive in time to send to Balboa and in view of Mr. Parkin- 

 son's surmise that the cementing material used by the 

 makers softens at the temperatures reachedon the Car- 

 negie it has seemed better to repair No. 5503 in such a 

 way as to avoid such a source of failure and return it to 

 the Carnegie rather than to send the duplicate instrument 

 and run the risk of a repetition of this type of failure. 



A P\irther Comparison of Penetrating Radiation 

 Measurements with penetrating radiation apparatus 1 

 and Giinther and Tegetmeyer No. 5503 indicates that the 

 latter instrument began to act abnormally on July 19, 

 1928. Most of the measurements after that date yield 

 values of R which are so near the residual ionizationfor 

 this instrument (No. 5503), as reported by Dr. Kolhors- 

 ter, that they obviously are in error. From Mr. Parkin- 

 son's diagnosis of the ailment, it appears that the change 

 in capacitance due to the proximity of the charging arm 

 may be sufficient to account for the change in the rela- 

 tion between the values of R obtained with the two in- 

 struments. This appears especially likely when it is 

 noted that an increase in capacitance of 0.3 cm would 

 account for the difference. 



The Performance of Penetrating Radiation Appara - 

 tus 1 according to this examination apparently was very 

 good until some time early in August 1928. After that, 

 however, departures in the relations between values ob- 

 tained with the two instruments occur and in such direc- 

 tion as to indicate that the values from penetrating radi- 

 ation apparatus 1 are too small, in fact, sometimes less 

 than the value of residual ionization which was deduced 

 from the earlier and more consistent data. Since the 

 observations are taken so that loss and gain due to de- 

 fective insulation on the central system should just bal- 

 ance, this possible explanation seems excluded. Other 

 instrumental factors which may diminish the charging 

 rate of the electrometer are: progressive changes in 

 the insulation of the battery circuits or a changing bat- 

 tery e.m.f. The latter should have no effect, however, 

 provided the insulation on the battery circuits is ade- 

 quate and the balancing condenser is in proper adjust- 

 ment. If, however, the capacitance of the balancing con- 

 denser has in some way increased, that fact alone would 

 account for the diminished values of R. Another possi- 

 bility is that the residual ionization of penetrating radi- 

 ation apparatus 1 has changed, but this seems unlikely. 

 These various possibilities are mentioned in the hope 

 that they will suggest tests or observations that may 

 disclose the cause of this diminution of R, provided it is 

 of instrumental origin. 



If notes describing such tests and observations are 

 entered in the operating records, they will be helpful in 

 making analyses as well as in appraising the data. Even 

 a brief indication of such matters as, e.g., the times 

 when the insulators were cleaned, the drier was renewed, 

 various adjustments were made with some details as to 

 their nature, at times may be of considerable value if 

 for no other reason than allaying a doubt as to the value 

 of a group of data. 



BALBOA, CANAL ZONE TO CALLAO, PERU, OCTOBER 25, 1928 TO JANUARY 14, 1929 



General. --With the exception of October 27, and of 

 the seven days during which the vessel was anchored off 

 Easter Island, observations of the atmospheric-electric 

 elements have been made daily throughout the period 

 covered by this report. Some interesting effects of local 

 meteorological conditions were noted during this period. 

 Among these may be mentioned (a) the effect of rain on 

 conductivity, October 28, and (b) the effect of fog on ion 

 concentration and conductivity, December 22. Weather 

 conditions, apart from the period October 26 to Novem- 

 ber 4, have been generally favorable. Eight complete 

 24-hour diurnal-variation runs have been made. 



Potential-Gradient Recorder. --The sloping collector 

 rod which had been installed at Hamburg was still in use 

 during the week following departure from Balboa, but 

 in the rough weather encountered, the rod began to be 

 twisted round by the wind and by the excessive rolling of 

 the ship. On two occasions the rod came apart at the 

 soldered joint near the lower angle and it became obvi- 

 ous that it would be dangerous to continue to use a col- 

 lector rod of this type as it is impossible to anchor it 

 without the introduction of another insulator and, there- 

 fore, another possible source of leakage. An attempt 

 was made to hold the rod in place with wires stretched 



