2l6 TRANSACTIONS OF ROVAL SCOTTISH ARBORICULTURAL SOCIETY. 



treated of in the Transactions, and the condemnation of the 

 old forest plough. 



The morning of the 12th July was given up to a critical 

 examination of the forest school of Biesenthal, the discussion 

 being opened by an address by Forstmeister Leising, who 

 described the history and present treatment of the forest. 



In the afternoon the town forest of Eberswalde was visited, 

 and a most instructive lecture was given on the silvicultural 

 treatment of a pine forest. This led to a most animated 

 discussion, and the labours of OberfcJrster Haak were highly 

 appreciated. 



The 13th July was entirely occupied by a lecture by Dr 

 Albert regarding the newest researches on soils. This lecture, 

 accompanied by numerous experiments, started with the famous 

 discovery by Graham of colloids. But though Graham was 

 undoubtedly the founder of the chemistry of colloids, his original 

 division between crystalloids and colloids is at present only of 

 historic interest. It has since been ascertained that colloidal 

 or non-colloidal conditions are different phases of matter, and 

 that every substance can exist in either form and change from 

 the one to the other. To follow in detail Albert's lecture, in 

 which he gives the general foundations of the chemistry of 

 colloids, would necessitate the taking up of all the pages of 

 the Transactions, which would not be reasonable. 



He explained how intimately the colloid theory was connected 

 with our knowledge of forest soils, especially in regard to humus, 

 and showed how simple and clear the knowledge of colloid 

 chemistry made many formerly more or less unexplainable 

 occurrences in the soil and the growth of plants. There was a 

 time, not so long ago, when all such unexplainable occurrences 

 were considered to be due to bacteria, and he warns against 

 overhaste in the acceptance of the ne^^ theory, which, though 

 to all appearance crystal-clear, requires still deeper research 

 before its foundation and scope can be considered established 

 on a sufficiently firm basis. 



After an interesting morning lecture by Dr Franz Schwarz on 

 the influence of lime on the growth of plant life, demonstrations 

 took place in the experimental garden of the mycological 

 section of the Academy, and ex[)lanations were offered by 

 the Director of the Academy, Dr Moller. 



The garden, several acres in extent, was established in 1902, 



