EXPERIMENTS ON THE CULTURE OF TURNIPS. 



253 



Crlancing at the weights of the samples, it is at once apparent 

 that they form a fair corresponding index to the weight of the 

 crop. 



In 1879,1 was frequently told that the excessively wet season 

 of that year was the cause of the bad results shown by soluble 

 phosphates. T had personally no definite opinion on the subject, 

 but resolved to test the drainage water for phosphoric acid, in 

 order to learn if it was carried off in the drains, as being the 

 most likely if not the only effect excessive rain was likely to 

 cause. Circumstances fortunately gave me a good opportunity of 

 doing this in an effective manner. 



The leading drain selected had an infall of about twenty acres, 

 which was all under root crop this year, and heavily dressed with 

 farmyard and artificial manures, last year also receiving a heavy 

 dressing of soluble manure to the grain crop. 



After the manure had been applied to the root crop of this 

 year, there was a continuous drought for several weeks, with no 

 rain sufficient to reach the drains. At this time I sampled the 

 water when the pipe was only discharging a tiny, stripe — not 

 more than a gallon in ten minutes. A fortnight later a deluge 

 of rain occurred, and in consefpieuce the drain was running full 

 pipe, with a considerable pressure, discharging many gallons per 

 minute. I sampled the water after the drain had run in this 

 way for about ten hours. Another lieavy rain occurred about 

 ten days later ; the water of this drain was sampled for the third 

 time. I sent these sanqdes of water to a chemist for examina- 

 tion, and received the following report : — 



" The first sample you sent contained nitric acid, but in very 

 small propjortion, what might be called a trace. Of phosphoric 

 acid it contained none, or an exceedingly small quantity. Of 

 ])otash, there was what might be called a faint trace. In both 

 of the second samples there was a large ([uautity of nitric acid. 

 Of potash, however, there was only a trace, and of ])hosphoric 

 acid there was either none at all, or the quantity was so snuill 

 as hardly to be recognisable." 



Judging from this report, the excessive rainfall had evidently 



