The methods of continuius measurement of the flow rate of exhaust gas were experimentaly examined on driving cars using several instruments based on different principles of the measure, in order to develop the proportional sampling system of the automovile exhaust gas. The results obtained are as follows.
1.The values measured by hot wire anemometer were always sligtly larger than those derived from the measurement of the total volume of exhaust gas which was collected into the plastic bags at the exit of tail pipe during 10 sec. on every load of engines.
2.Biram type anemomerter method gave values slightly inferior to those by Pite tube method, and former was little influenced by the setting position of the probe. On the other hand the later had a higher sensitivity for the fluctuation of flow rate.
3.The measurements of moisture contents in exhaust gas were done by applying the principle of thermister type psychrometer, Assman type psychrometer and calcium chloride adsorpion tube, so as to calcalate the gas velocity based on the their density.
4.The measurements of exhaust gas flow rate on idling were carried out by Biram type anemomerter, Pite tube and thermister methods, and it was recognized that a considerable differences were observed between the data by Biram and Pito methods, and this would be brought about by the difference of measuring point.
5.Applying these methods, the flow rates of exhaust gas of the test cars were measured on city road driving. And it seemed that the Biram type anemometer was the most suitable to the measurement of flow rate of automoble exhaust gas which are emitting succesively with large fluctuation.

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New measuring method of rain water by a rain water monitor with personal computer was studied. The method was as follows; the data of small unit time of pH, electric conductivity (E. C.), temperature of rain water and rainfall measured with a commercially available rain water monitor were stored by a digital data recorder and then treated by a personal computer.
This system could rapidly collect data at 1 minute intervals, mean values of pH and E. C. corrected at 25°C, taking rainfall into consideration, and mean values of every 1 hour and every 0.5mm rainfalls. The proposed method can be utilized for various acid rain studies.
The data of pH, E. C. and rainfall obtained by chemical analysis with regard to rain water collected at one time of every rainfall agreeded with those by this monitor.
The concentrations of SO^2-₄ and NO^-₃ in the rain water could be estimated from E. C. measured with this monitor.

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