General Notices. 



225 



never previously been done. It will then appear, as we think, that the greater 

 number of plants, both ligneous and herbaceous, hitherto considered as 

 species, will not even continue to exist as varieties. On the other hand, as 

 varieties which have been created by difference of locality disappear, others 

 will be originated through culture and cross-fecundation. It must never be 

 forgotten, that varieties of plants originated through culture afford by far the 

 most valuable products for mankind, and therefore, in point of utility, are of 

 much greater interest than either natural varieties, that is, such as are pro- 

 duced by difference of locality and climate, or even species. (Extracted 

 by T. W.) 



Effect of Mercurial Vapour on Vegetation. — A paper was read by Mr. 

 Fortune, the superintendant of the hothouse department in the Society's 

 Garden (Feb. 16. 1841), upon the effect of mercurial vapour on vegetation. 

 The author stated that in consequence of reports that wood prepared with 

 corrosive sublimate, under Kyan's patent, was injurious to vegetation, a 

 series of experiments had been tried in the garden for the purpose of ascer- 

 taining how far these opinions were well founded. In one experiment a small 

 portable greenhouse was prepared with Kyanised wood, and, thus pickled, 

 was introduced into the atmosphere of plants under hand-glasses, but without 

 injurious effects in such cases. But when Kyanised wood, or shavings mois- 

 tened with corrosive sublimate, or crude mercury, or salts of that metal, 

 were introduced into vessels containing plants exposed to the dampness and 

 high temperature of a hothouse, in every such case the plants became sickly, 

 recovered when removed from the influence of the mercurial vapour, and 

 sickened again when again exposed to it. {Proceedings of the Hort. Soc. for 

 1841, p. 203.) 



Comparative Value of Coke and Anthracite as Fuel in Hothouses. — Mr. For- 

 tune presented, from the hothouse department, the following " Results of some 

 comparative Experiments with Coke and Anthracite, consumed in the conical 

 hot-water Boilers, invented by J. Rogers, Esq." The experiments are now 

 ended which have been in progress throughout the winter, to test the efficiency 

 of the improved conical boiler, and to ascertain whether coke or anthracite is 

 the cheapest and best fuel to burn in it. So far as the boiler is concerned, 

 the results have been perfectly satisfactory. When the apparatus connected 

 with it is strongly constructed and well built in, as it has been in this case, it 

 is easily managed, and as economical as any boiler with which I am acquainted. 

 I think, however, its chief recommendation is, the kind of fuel which it will 

 burn (coke or common cinders); and the certainty with which it maybe left, with- 

 out any attention for ten or twelve hours, to keep a stove to 60° in the midst of 

 winter with the external atmosphere so low as 6°, or even zero of Fahren- 

 heit. This is owing to the manner in which the fuel falls down into the fire, 

 to the great quantity of air which is continually rushing in through the bars, 

 and to the complete power of regulating the supply of this, when the appa- 

 ratus is as it ought to be. The fuel was tried in the following manner. 

 In the months of October and December we burnt coke, in November and 

 January anthracite, and in February coke and anthracite every alternate night. 

 The results, together with the mean temperatnre of the different months are 

 now laid before the committee. The stove was kept between 60° and 65°. 





Nature of 

 Fuel. 



Quantity of Fuel 

 consumed. 



Mean Temperature of the 

 Months. 



Max. 



Min. 



Sun. 



October 

 November - 

 December - 

 January 



Coke - 

 Anthracite 

 Coke 

 Anthracite 



43 bushels 

 1 ton 5 cwt. 

 92£ bushels 

 lton 16 cwt. 3jlb. 



56-32 

 49-96 

 37-55 

 39-90 



36 96 

 36-46 

 26-45 

 28-61 



74-39 

 54-66 

 38-03 

 41-11 



3d Ser. — 1842. IV. 



