560 



{Willd.) found hv liim in Ladiston Woods, Miilling-.ir, Westmeath, Ireland, in July 

 last. Mr. Robert Castle jnesentod a spoeimou of Araiiearia exeelsa. Col. Jaekson 

 pi-esented an interesting oollecliou of foreign plants. The President presented the 1st 

 faseieulus of Leefe's British Willows : and British plants had been reeeivcd from 'Mr. 

 T. B. Hall, Dr. Ayres, Mr. Henfrey and Miss Beever. Donations to the library were 

 announeed from Pi-ofessor ^leneghini, Mr. W. M. Chatterley and the American Phi- 

 losophieal Society. 



JMr. Arthur Henfrey read a paper " On the British Species of Statice.''* Speci- 

 uiens of British and foreign species in the Society's collection were exhibited. — G.E.D. 



MIOROSCOVIOAL SOCIETY OF LONDON. 



March lo, 1S43. — George Loddiges, Esq. in the chair. 



Read, a paper from the Rev. J. B. Reade, entitled " Microscopic 'Chemistry, No. 

 IT." The paper was headed *' On the existence of Ammonia in Vegetable Substances 

 described as containing Nitrogen." After stating that very minute portions of sul- 

 phate of lime in snow may be rendered manifest by means of the microscope, and also 

 that the almost inappreciable quautitiy of ammonia mentioned by Liebig as existing 

 in the atmosphere would be capable of detection by the same means ; the author pro- 

 ceeded to show the existence of ammonia in the seeds of plants, which he stated may 

 be rendered apparent by burning the common field bean in a spirit-lamp, until tlame 

 and smoke entirely cetvse. The g-as given oft' is to be received on slips of glass 

 moistened with pure hydrochloric acid. The salt thus obtained he describes as 

 a Siilt of ammonia, which he considei"s to be produced by the decomposition of an am- 

 iuoniac;il salt previously existing in the bean, and not by the destructive distillation of 

 an organic body in contact with the atmosphere. This presence of ammonia the au- 

 thor looks upon as proved in various ways : — 1. By the before-mentioned production 

 of crystals of hydrochlorate of ammonia on slips of glass, when the gas from the bean 

 is exposed to the vapour of volatUe hydrochloric acid. 2. By the odour of this gas 

 when received into an eight or ten ounce bottle, being clearly that of ammonia. 3. By 

 the production of crjstals of bi-tartrate of ammonia on the addition of a little tartaric 

 acid to the hydrochlorate. 4. By the action of the supposed ammouiacal g-as on test- 

 papers, furnishing a proof of the presence of volatile alki\li. And lastly, by an expe- 

 riment in which he sublimed over hydrochlorate of ammonia, in an unchanged state, 

 into a drop of distilled water. The acid with which the ammonia is combined he sup- 

 poses in some instances at least to be silicic acid. In answer to an objection made to 

 these views, that the ammonia is chemically fonued by the destructive distillation of 

 the vegetable compoimd in contact with the atmt^sphere, the author adduced what, in 

 his opinion, must be considered both negative and positive evidence ; the former being 

 foimded on the known reluctance of nitrogen to enter into combination with all other 

 substances ; the latter principally from the evolution of ammonia from bean-meal, 

 heated in a glass tube with the month inserted into hydrochloric acid, thus preventing 

 contact witli the atmosphere. The anthor concludetl by describing a method of readily 

 obtaining as a standard of measurement, a minute quantity of hydrochlorate of am- 

 monia, equal to about the ^^^j^ of a grain. 



* This paper will most probably appear in our nest number. — Ed. 



