The diurnal variation of atmospheric potential gradient at eight stations in the Japan archipelago was investigated and the following results were obtained. 1) Times of occurren c e of the maximum of diurnal and semidiurnal variation generally coincide with one another at stations of rural situation. 2) In larger cities the variation of the potential gradient is controlled mostly by the electrical conductivity of the lower stratum of the atmosphere. 3) In rural c onditions only the semi-diurnal component of the variation of the potential gradient is controlled by the conductivity of the lower atmosphere and the diurnal component is controlled by a cause in the upper atmosphere. 4) The time of occurrence of the maximum of diurnal component of potential gradient in the Japan archipelago is 21-23h, GMT. 5) The diurnal component of the potential gradient is composed of the unitary variation and the local time variation. The latter variation has a close relation with the character of weather around the station.
Improvements o f the remote-reading and -recording thermometer with sealed carbon filament are described. As its application, a portable remote temperature indicator, a remote sea-depth and -temperature indicator and an automatic temperature regulator are reported.
The author observed a drift current in a rising state using his newly designed current meter , and he could distinguish in a recorded chart a rising drift current, a proper ocean current and an apparent ocean current caused by a swing of the current meter due to the yawing, pitching and rolling of the research ship “Asasiwo Maru” in bad sea conditions.
In eutropic lakes or coas t a l waters, a marked diurnal variation of oxygen content is found. There are two types of v a riations. In one of them, a minimum occurs mostly at about 6h and a maximum at about 17h. This type of variation is often seen in stable and homogeneous water masses. In the other type, minimum and maximum occur at different hours from the above-mentioned. In this case, the influence of diffusion and advection or convection upon the diurnal variation of oxygen content must be considered. In this paper, the former case is chiefly treated. In this case, the amplitude of the diurn a l variation depends upon the intensity of radiation, the d u r ation of insolation, water temperature, number and size o f phytoplanktons, etc. Indeed, the amplitude is larger on a clear day than on, a cloudy day and it is also larger in summer than in winter. It was found by calculation that the diurnal variation should have a minimum and a maximum at a certain time distance respectively before and after the noon. By using the data of the diurnal variations of dissolved oxygen, the amoun t of the oxygen production or consumption during a whol e day is computed. Assuming a certain size and number of phytoplanktons, computed values agreed well with the observation.
The present, author prop o sed a new procedure of chlorinitydetermination of sea water. In this method, it is required to take only 1.5 ml of sea water which is one tenth of the quantity of sample in the standard method. Consequently, the quantity of silver nitrate solution also can be reduced to one tenth. A pipette and a burette are made specially and used in this micro-method. The graduation of the burette is the same as in the Knudsen's burette, which enables us to read the chlorinity directly. The author used a mixed solution of uranin and starch as an indicator. The mean deviation of this method is about 0.01 %. Another merit of the method is to save much time, within the allowable limit of accuracy.