CONTRIBUTIONS FROM THE WISLEY LABORATORY. 321 



tion was similar, it does not appear that the small rainfall at the time 

 of growth of the turnips in that series is to be blamed for the 

 comparatively small benefit derived from the use of the peat, though 

 it may have had some influence in that direction. It is to be remem- 

 bered, however, that the soil was in a moister condition at the earlier 

 date than at the later, and would therefore assist in-making available 

 the constituents of the peat. 



Experiments in 1915. 



A fourth consignment of about 1 cwt. of bacterized peat was received 

 from Professor Bottomley at the beginning of May 1915. It had 

 been designed to carry out a number of tests with this in the 

 Laboratory, as there are many questions of great interest involved, 

 but absence of laboratory accommodation during building operations 

 and disorganization of the staff owing to the war prevented this. 

 Two series of tests (Series IV. and V.) were, however, carried out with 

 it during the summer. 



The peat received was dark brown in colour and in small particles, 

 and was evidently made of the same type of material as before. 



V. Series 4. — Experiments under Glass and in the Open. 



The plants chosen for this series of experiments were radishes 

 (' French Breakfast '). The pots used were 10-inch pots, and the 

 loam of good fibrous quality. 



Three pots containing 3 parts of loam and 1 of peat were sown 

 and grown in a cold house, together with six pots containing loam 

 alone. A similar set was placed outdoors and covered with wire to 

 protect them from the birds. The seeds in the soil containing peat 

 grew very badly, and most of the seedlings both outdoors and indoors 

 sickened and died, so that only twenty reached maturity in the three 

 pots indoors and fourteen in those outdoors. The same quantity of 

 seed was sown in each pot, and the plants grew away much better in 

 the pots containing loam alone, the six pots indoors yielding when 

 the roots were pulled and weighed in mid-August 123 plants, those 

 outdoors 112. These inequalities in number render any comparison 

 of weights unprofitable, and the only case where there were equal 

 numbers of plants in the pots containing loam alone and loam and peat 

 respectively under the same conditions was one outside. Here the 

 twelve plants in the " loam " pot gave a total weight of 274 grams, 

 the twelve in the " loam and peat " pot 267 grams, the relative weight 

 of the tops as compared with the roots being greater in the latter than 

 in the former. 



The seedlings in the loam-peat pots had, at first, the appearance 

 of suffering from manure poisoning. 



VI. Series 5. — Experiments in the Open in Ordinary Garden Soil. 

 The plant used in this series of experiments was Turnip ' Early 



White Stone.' The site was on ground well dug in the previous spring, 



