Proceedings of Learned Societies. 395 



It is a slow growing tree, and forms cart-loads of hard roots, which 

 fill and cover the ground where it stands. When, after several 

 hundred years, the trunk decays, the bark still remains alive. As 

 the decay progresses, the tree splits, as it were, into two, three, or 

 more sections. The hark twists and curls round each of these 

 decayed sections, and unites on the other side. Thus, instead of 

 the old tree, we have in its place two, three, or more, apparently 

 separate, although in reality all growing from the same root. When 

 these in turn die, new shoots spring up from the old roots, and thus 

 the life of the tree is indefinitely prolonged." Dr. Bennett gives an 

 interesting plate of grand old trees formed, upon this plan. We 

 hope his book will help to convert invalids into observers of natural 

 objects. The want of mental occupation is a powerful hindrance to 

 the comfort, and often to the cure of persons driven from their 

 homes in search of health. 



PROCEEDINGS OF LEARNED SOCIETIES. 



Br W. B. TEGETA1EIEE. 



LIVERPOOL PHILOSOPHICAL SOCIETY. 



Ventilation op Sewers. — At the last meeting of this society, 

 Mr. Higginson drew attention to the extract from the Scientific 

 Sevieiv on the ventilation of sewers, stating that a French chemist 

 had proposed to draw from the sewers a supply of air for the 

 support of the combustion of furnaces in factories, thus destroying 

 the noxious gases by combustion, and supplying fresh air to the 

 sewers. It was stated that the plan was already in use on a small 

 scale. Mr. Higginson stated that he had suggested the same plan 

 to the Social Science Association at Liverpool in 1858. 



The advocates of this mode of ventilating sewers seem to be un- 

 aware of a fatal objection to its employment, namely, that the gases 

 given out by the decomposing sewage consist chiefly of carbu- 

 retted and sulphuretted hydrogen, that these are combustible, and 

 capable of forming an explosive mixture with atmospheric air. 



The plan was tried in London many years since, during one of 

 the earlier outbreaks of cholera, and a very serious explosion took 

 place in the sewers of the neighbourhood in consequence. As it is 

 impossible to prevent such a result from recurring, or to predict 

 the extent of damage that might ensue, the proposal cannot be 

 regarded as safe. 



CHEMICAL SOCIETY.— Nov. 2. 



Discovery op Cerium in England. — Professor A. Church ex- 

 hibited several new minerals which had been recently discovered in 

 Cornwall. The most interesting of these was a hydrated phosphate 



