138 PROCEEDINGS OF SECTION B. 



Monday, September 3. 



The President, Mr. J. G. Black, M.A., DSc, Professor of Chemistry 

 and Mineralogy, University of Otago., New Zealand, in the Chair- 



The following papei's were read : — 



1— ON THE DISSOLVED MATTER CONTAINED IN 

 RAIN-WATER COLLECTED AT LINCOLN, CAN- 

 TERBURY, NEW ZEALAND. 



By George Gray, F.C.S., Lecturer on Chemistry, School of 

 Chemistry, Lincoln, New Zealand. 



For the past four and a half years samples of the rain-water, 

 collected at the School of Agriculture, Lincoln, have been analysed, 

 and the results published in the reports of the school issued from 

 time to time. The investigation is being still continued ; in the 

 present paper the results, so far obtained, are collated and 

 averages deduced. 



In the collection of the samples of rain-water as much care as 

 possible is exercised in order to prevent contamination. The 

 collecting vessels, which are stationed at the Meteorological 

 Observatory of the School, consist of glass funnels eight inches 

 in diameter, the stems of these are inserted into the necks of 

 " Winchester " quart bottles so that the rain as received comes 

 only into contact with glass. These collectors, of which there 

 are three, are cleansed from adhering impurities occasionally. 

 The rain-water as collected is stored in other stoppered bottles 

 until the end of each month, when the whole is thoroughly mixed 

 and portions taken for analysis, There exists considerable diffi- 

 culty in collecting samples perfectly free from extraneous matter, 

 as dust, pollen, insects, etc., will find their way into the vessels in 

 spite of all care. In removing such matters, which is always 

 done as early as possible, decantation is resorted to, since it is 

 found that filter paper always contained sufficient ammonia to 

 vitiate the results, unless washed thoroughly five or six times 

 with specially prepared distilled water. 



With the exception of the water collected during the year 

 1887 the analysis was made as soon as possible after the month 

 in which the rain was received. When the investigation was 

 commenced it was intended only to analyse the monthly rainfall 

 extending over three years, and afterwards to analyse the mixed 

 annual rainfall, but in consequence of the abnormal I'ainfalls of 

 1886 and 1887 and the interesting nature of the results, it was 



