Miscellaneous. 30 1 



he had seen the true Mygale avicularia alive in England, washed ashore from a 

 wreck on the coast of Essex. 



Mr Rootsey gave a detailed account of his experiments upon the root of Man- 

 gel- Wurtzel, made for the purpose of ascertaining the probability of its being 

 successfully employed in this country for the manufacture of sugar. He exhi- 

 bited specimens of this sugar of good quality, and considered that a judicious se- 

 lection of the soil in which the mangel-wurtzel was to be grown might certain- 

 ly render it an advantageous speculation. His opinion was founded upon the 

 uses to which the refuse of this plant might be applied, after extracting of the 

 juice from which the sugar had been obtained. Of this refuse an excellent kind 

 of malt might be prepared, from which he had brewed good beer, and extracted 

 an ardent spirit. It was also found serviceable for fattening cattle. He stated, 

 contrary to the received opinion, that this plant was liable to the attacks of in- 

 sects, as he had found it infested by the Haltica nembrum. 



Mr G. Webb Hall, as a practical agriculturist, entirely differed from Mr Root- 

 sey in supposing that the mangel-wurtzel might be grown to advantage for the 

 purpose of making sugar. 



Professor Henslow exhibited some crystals of white sugar-candy, obtained 

 from the flowers of Rhododendron Ponticum. A detailed account of these has 

 since appeared in Loudon's Magazine of Natural History for September 1836. 



Mr G. Webb Hall read a paper " on the Acceleration of the Growth of Wheat." 

 By a judicious selection of seed, and a proper choice of situation, Mr Hall had 

 been able to procure a ripe crop in the middle of August from seed sown early 

 in March. Dr Richardson referred to a remark of Humboldt, that the Ameri- 

 can crops generally were ripened in ninety days from the period when they were 

 sown ; and suggested the propriety of procuring seed from Hudson's Bay, where 

 he had found the crop to ripen in seventy days. 



A mode of accelerating the germination of seeds was noticed by Professor 

 Henslow, who stated, that he had produced this effect by boiling the seeds of a 

 Cape Acacia. The details of this experiment are given in Loudon's Magazine 

 of Natural History for September 1836. Mr Hope referred to a custom in 

 Spain of partially roasting the corn before sowing it, for the purpose of destroy- 

 ing an insect by which it was infested. 



Dr Daubeny stated, that he had commenced a series of experiments for the 

 purpose of ascertaining the effects produced by arsenic on vegetation. He had 

 been informed that nothing but a few Leguminosse would grow in a particular 

 district of Cornwall, where the soil contained about 50 per cent, of the sulphu- 

 ret of arsenic, and the rest of which was chiefly sulphuret of iron and silica. 

 He had ascertained that a little of the sulphuret of arsenic produced no effect on 

 vegetation, probably from its not being very soluble, though it was certainly 

 taken up in a certain proportion. He had also ascertained that plants would 

 bear being watered with a solution of arsenious acid, in much greater proportion 

 than was hitherto considered possible, without injuring them. 



Tuesday, August 23d — Dr Richardson's Report continued. 

 Mr Bowman read a communication on the Longevity of the Yew Tree. He had 

 examined several young trees whose precise ages were known, and had ascer- 

 tained that their average rate of increase for the fiist 120 years was at least two 

 lines, or the sixth of an inch per annum. He then proceeded to give his mode 

 of estimating the ages of two very large trees, from the trunks of which he had 

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