REPORT ON ATMOSPHERIC ELECTRIC WORK 



37 



Penetrating Radiation Apparatus 1. --Between De- 

 cember 1, 1928, when the fiber was transferred to the 

 ion counter, and December 13, when a fiber from a 

 spare electrometer was inserted, this instrument was 

 idle. At all other times it has functioned normally. On 

 December 28 the sodium drying tubes were changed, the 

 same precautions as before being observed to avoid un- 

 due change of the air contained in the apparatus. 



Nuclei Counter 4. --On December 18, during one of 

 the observations of a diurnal -variation series, the re- 

 ceiver came apart from the pump stem. An effort was 

 made to resolder the parts, but the heat generated to 

 run the solder loosened the tube of stopcock A, so that 

 this came off also. Three more attempts were made to 

 resolder the parts and to make the receiver airtight 

 when the cocks are closed. It appeared for a time that 

 this had been successfully done but evidences of leak 

 were apparent again on January 10. The values obtained 

 since the repair are very erratic and we have no means 

 of telling whether they are correct. It would seem ad- 

 visable, therefore, for us to have a second Instrument 

 on board. 



Batteries. --The silver chloride batteries have re- 

 mained in good shape since the replacements were made 

 in Balboa. Four bad cells have developed in one battery 

 and these were cells which were in the battery when 

 leaving Washington. It has been necessary to put only 

 two of the Eveready batteries into service to replace two 

 Burgess "B" batteries used for the auxiliary potential 

 of the potential gradient recorder which had been short- 

 circuited through a defect in the marine plug on the 

 quarter-deck. We shall have use for more of the "B" 

 batteries purchased in Balboa when the Kolhorster in- 

 strument is in use again. 



Radioactive Content Apparatus. --Attempts have been 

 made to maintain a high potential on the outer cylinder, 

 but without success. With the atomizer, the potential 

 builds up to about forty divisions and immediately falls 

 to zero. With the old tjrpe multiple -nozzle sprayer, so 

 far it has not been possible to obtain any deflection of 

 the electroscope. Further efforts will be made while the 

 vessel is at Callao. 



Comments 



Potential-Gradient. --Since the change in the collec- 

 tor on the potential-gradient recorder did not make the 

 reduction factor much greater than unity, and since the 

 reduction factor for different boom positions does not 

 differ a great deal, the new arrangement no doubt will 

 prove satisfactory. The great number of potential gra- 

 dient diurnal-variation records being obtained is grati- 

 fying, especially in view of the fact that these appear to 

 be quite reliable. 



We are unable to find a satisfactory explanation for 



the distressing experience with the electrometer fibers 

 unless it be that the fibers were too heavily gilded. The 

 entire "sputtering" system was thoroughly cleaned and 

 repaired and arranged to "sputter" platinum instead of 

 gold. Accordingly it is hoped that the new platinized 

 fibers will prove more durable. The item regarding the 

 drift of fibers brings to mind similar experience at the 

 laboratory; however, in certain of these cases the cause 

 was not defective fibers but resulted from charges which 

 had been developed on the insulators while these were 

 being cleaned. A drift owing to this cause will disappear 

 in a moment if the insulator is exposed directly to the 

 action of the collector or of a burning match held within 

 approximately one inch from its surface. 



Batteries. --The report regarding the batteries is 

 reassuring. From the experience reported on the earli- 

 er part of the cruise, together with recent reports from 

 the observatories, we became convinced that the silver 

 chloride batteries obtained in the last year or two are of 

 inferior quality and we feared that considerable trouble 

 with these might be encountered during the remainder 

 of the cruise. It is also a matter of interest that the 

 "B" batteries originally put on board have held up so 

 long. If these had lasted only as far as Balboa, they 

 would have been considered satisfactory. 



Nuclei Counter. --The trouble with nuclei counter 4 

 was owing to the poor workmanship put into it by the 

 makers. It is understood that the instrument at Huan- 

 cayo was obtained to replace counter 4' and it is hoped 

 this will prove satisfactory. As stated before, nuclei 

 counts in recent years have become recognized of great 

 importance in atmospheric-electric studies. According- 

 ly it is desirable that such counts should be made in con- 

 junction with ion counts, conductivity, and penetrating 

 radiation measurements whenever possible. 



Radioactive Content Apparatus. --The difficulty with 

 the radioactive content collector no doubt is owing to the 

 insulators becoming fouled by the spray from the atomi- 

 zer of the high potential generator. If this part can be 

 enclosed in a sheet-metal shield which Is so made that 

 the spray does not readily come into contact with the 

 high-potential insulators, then it is believed that the 

 charging device will work satisfactorily. This shield 

 should surround all the parts and have a tube of about 

 one and one-half inches diameter which leads to the out- 

 side air or into the lower parts of the fan compartment. 

 The suction of the fan with the latter arrangement may 

 assist in giving the desired circulation inside the shield. 

 It is hoped that it may be possible either to construct 

 such a shield on board or have it made up at one of the 

 ports of call. If, however, this will not be possible be- 

 fore reaching San Francisco and in case no other means 

 is found which will bring about satisfactory operation of 

 this apparatus then the office should be advised soon so 

 that there will be time to construct something of this 

 sort to be installed at San Francisco. 



CALLAO, PERU TO PAGO PAGO, SAMOA, FEBRUARY 5 TO APRIL 1, 1929 



General. --Observations of the atmospheric-electric 

 elements have been made practically dally during the 

 period of days at sea covered by this report. Weather 

 conditions between February 5 and March 5 were gener- 

 ally favorable; after that date, frequent squalls, calms, 

 and heavy rolling in swells have tended to produce ab- 

 normal values. Complete diurnal -variation rims. 



through twenty-four hours, were made on February 10 

 and 11, 18 and 19, and 26 and 27; incomplete runs, aban- 

 doned through squalls and generally abnormal conditions, 

 were begun on March 10, 25, and 27. Doubtless it has 

 been noted that the general program of observation dur- 

 ing these diurnal-variation runs is slightly different from 

 that of previous cruises. With the present program 



