262 Report of the Edinburgh Botanical Society. 



for botanical specimens generally, is to sew up each in cloth of any kind, with 

 a wooden or tin label attached to it, and to put the whole in a barrel, con- 

 taining the solution of salt, and of such size that the specimens are loosely 

 packed, and yet cannot easily change their position. He has frequently received 

 specimens sent in this way, in a state of complete preservation, from Ceylon, 

 the Isle of France, and the West Indies, although four or six months elapsed 

 before they readied their destination. 



" Solution of salt is comparatively inapplicable, however, where the fruit 

 is very pulpy ; in such fruits, for example, as Sulanum Ly coper sicicm, or lemons 

 and oranges; because the fruit shrivels by exosmosis of its fluids. Diluted 

 pyroligneous acetic acid, diluted to the density of 1008, sometimes answers 

 well in such circumstances ; but after a few years the texture of the speci- 

 mens becomes so pulpy and brittle, as not to admit of their being handled, 

 and most colours are in no long time more or less altered. Spirit, which is 

 most generally used, speedily renders all colours alike brown." 



May 10. — " Mr. Macaulay read the first part of a paper ' On the Effects of 

 Vegetation on the Atmosphere,' in which the influence of the vegetable king- 

 dom on the composition of the atmosphere was treated. After detailing 

 various experiments, tending to show that different natural families may differ 

 in their effects on the atmosphere, and giving an abstract of the researches of 

 Priestley, Senebier, Berthollet, Ellis, Saussure, Burnet, Morren, Daubeny, 

 and others, Mr. Macaulay concluded by presenting a series of propositions, 

 which appeared to him to contain the present state of our knowledge on 

 this subject. A statement of the results of the enquiry will be given along 

 with the abstract of the remaining part of the paper, in which the influence of 

 the vegetable kingdom on the Temperature, Moisture, and Electricity of the 

 atmosphere will be treated." This promises to be a most valuable paper, 

 and we could wish to see it published at length. 



The list of contributors to the herbarium comprises a great many names, 

 among which is included that of W. Christy, jun., Esq., F.L.S., who pre- 

 sented the Society with about 8000 species and 15,000 specimens. This 

 gentleman is also one of the contributors to the library, and his donations 

 amounts to upwards of 60 different works, many of them of great rarity and 

 value. These are magnificent donations, worthy of the excellent individual 

 by whom they were made. 



The main object of the Botanical Society is the intercommunication of 

 dried specimens of plants ; and though, to many, this may appear a .matter 

 more of amusement than of use, yet, to all who wish to know the names of 

 plants when they see them, we consider dried specimens of very great im- 

 portance. However accurately plants may be described by botanists in 

 books, we can never be quite certain in the application of their description, 

 without the aid of a dried specimen or a coloured figure ; except in those 

 cases where the enquirer already possesses a knowledge of the majority 

 of species of the genus to which the species belongs that he is examin- 

 ing. Collecting and drying specimens, even though the names are not known 

 by the collector, is a very excellent mode of acquiring a taste or desire for 

 botanical knowledge; and when once any person has dried a few specimens 

 himself, so as to have an idea of the changes which they undergo in this 

 process, he may acquire the names of a great many plants, and be able to 

 recognise them in a living state, merely from recollecting their appearance 

 in his herbarium, or in his coloured plates. It is true, that knowing the 

 names, and being able to apply them to the plants, is nothing more than an 

 index to their history, properties, and uses; but every one must allow that the 

 possession of this index is of the greatest practical value. The intercommu- 

 nication of specimens among botanists is, therefore, of great use to them ; 

 and if those who are only beginning to study botany had an opportunity of pur- 

 chasing abundance of specimens correctly named, it would contribute greatly 

 to their advancement in the science. It will be seen from these remarks, that 

 we highly approve of this Society, and would advise such gardeners as have 

 an opportunity of collecting and drying specimens to belong to it. 



