CONTENTS. 



vu 



II. Farther Experiments and Obfervations on the Affeftions and Properties 

 of Light. By Henry Brougham, jun. Efq. — — ?• ^47 



Images by reflexion, inflexion, and deflexion of homogeneal light of different fizes according to the 

 diftance to which bodies aft on the particles of light. Phenomena explicable on this principle. 

 Colours in tranfparent plates — in metallic fpecula — and in lenfes, in confequence of minute imper- 

 feftions. 



III. Enquiries refpefting the Colouring Matter of Vegetables, and the A£tion 

 of Metallic Subftances and their Oxydes upon them ; together with a New 

 Procefs for obtaining Lakes of the moft intenfe and folid Colours. Read 

 to the National Inftitute (of France) 15 Vendemiare, in the Year VI. By 

 the C. Guy ton — — — — P- ^55 



Theory of the red colours of vegetables. The aftion of tin, or its oxyde, confifts in feizing the acid 

 of the red compound. Other metals prodvfce the fame effeft — but tungften moft eminently, be- 

 caufe infoluble in the mineral acids. Valuable lakes from the different vegetable matters, particularly 

 aloes. 



IV. Abftraft of a Memoir on Camphor and the Camphoric Acid, read to the 

 Firft Clafs of the National Inftitute of France. By Bouillon La Grange 



P- ^S7 



Procefles for obtaining camphoric acid. Combuftion of camphor with oxygenous gas. Charadlers of 

 camphoric acid. Conclulion. 



V. An Account of feveral new Experiments on Heat, with occafional Re- 

 marks and Obfervations ; and Conjeftures refpefting Chemical Affinity 

 and Solution, and the Mechanical Principle of Animal Life. ByBenjamiri 

 Count of Rurtiford — — — — p. 160 



Prefatory obfervation. Ineffeftual attempt to tranfmit heat downwards through a thin flratum of oil, 

 and of mercury, to a protuberance of ice. Conclufion that thefe fluids do not conduft. Obferva- 

 tions on the etie'^s of heat and cold in chemical folutions; — ^whether all changes of form may not 

 be true fufions and congelations, ice. Eleftive attraftions probably referable to the mere effefts of 

 heat. Water and brine do not mix, but by change of temperature. Curious inference with regard 

 to frefh-water lakes. Ice formed at the bottom of Water. Phenomenon of ground ice. Intenfe 

 ' heat in the midft of mafl'cs of cold liquids, and in other circumftances. Application to chemical 

 theory. Mifcellaneous experiments. 



VI. An Account of certain Motions which fmall lighted Wicks acquire 

 when fwimming in a Bafon of Oil ; together with Obfervations upon the 

 Phenomena tending to explain the Principles upon which fuch Motions 

 depend. By Patrick Wilfon, F. R. S. Edin.- and Profeffor of Praftical 

 Aftronomy, in the Univerfity of Glafgow — — — P- 167 



Defcrlption of a fmall float and wick, which when lighted circulates upon oil. Other attendant phe- 

 nomena. Deduftion of the caufe from the expanlion and circulation of fluids by heat. Other fafts 

 and experiments. 



VII. Experimental Refearches concerning the Principle of the lateral Com- 

 munication of Motion in Fluids, applied to the Explanation of various 



Hydraulic 



