814 Royal Society : — 



Acrylic alcohol, the history of which we have endeavoured to 

 sketch in the preceding pages, and in the study of which we are now 

 engaged, is the third term of a series of alcohols, which is parallel to 

 the ordinary alcohols of the formula 



Cn2Hn2 + 2 02, 



and the prototype of which is ethylic alcohol. The acid corre- 

 sponding to this alcohol is acrylic acid, as has been stated. Che- 

 mists are already acquainted with several homologues of acrylic acid, 

 which stand to the series of fatty acids in the same relation which 

 exists between our new alcohol and common alcohol. Cyanide of 

 acryle, which is readily procured by the action of iodide of acryle upon 

 cyanide of silver, but which as yet we have not been able to obtain 

 in a state of perfect purity, when submitted to the action of potassa, 

 will obviously furnish an acid, homologous to acrylic acid equally as 

 cyanide of propyle is transformed into butylic acid. 



We terminate this note with a synoptical table of the two homo- 

 logous groups. 



Group of Alcohols. Group of Acids. 



C, Ha O2 C, H4 O2 Methylic C3 O4 (Carbonic ?) C3 Ha O4 Formic 



C4 H4 O3 C^ Hfi O2 Ethylic C4 Hj O4 C4 H4 O^ Acetic 



Ce H« Oj Acrylic C9 Hr O^ Propylic Cg H4 O4 Acrylic Cg Hg O4 Propionic 



Cg Hh O2 Cr HjoOa Butylic €„ Hg O4 €« H^ O4 Butylic 



CioHjoOa C,oH,2 02 Amylic C,o Hf, O4 Angelic CjoH,o04 Valeric 



C12H12O2 C12H14O2 Caproic Ci2H,o04 C,2H,2 0i Caproic 



C,4 H,4 O2 C,4 H16 O2 Ci4 H,2 O4 0,4 H,4 O4 CEnanthylic 



CigH.gOa CigHigOa Caprylic C,6Hi4 04 C,a H,6 04 Caprylic 



CagHsgO, CagHagO, C36H34O4 Oleic Cj, Hgg O4 Stearic 



This table exhibits a considerable number of gaps, which the pro- 

 gress of science will not be long in filling up. Even now we have 

 established by experiment that bromide of amylene suffers many 

 changes, which are perfectly analogous to those which we have wit- 

 nessed in the acryle series, and even the derivatives of olefiant gas 

 appear to exhibit in many respects an analogous deportment. 



Feb. 21, 1856.— The Lord Wrottesley, President, in the Chair. 

 The following communication was read : — 



** Account of the Observations and Computations made for the 

 purpose of ascertaining the amount of the deflection of the Plumb- 

 Line at Arthur's Seat, and the Mean Specific Gravity of the Earth." 

 Communicated by Lieutenant-Colonel James, R.E., F.R.S. &c. 



Col. James begins by observing, that as the Royal Society has, 

 from the very commencement of the Ordnance Survey of the United 

 Kingdom, taken a deep interest in its progress, he has great pleasure 

 in announcing to the Society that all the computations connected 

 with the Primary Triangulation, the measurement of the Arcs of 

 > Meridians and the determination of the figure and dimensions of the 

 earth are now completed, and that the account of all the operations 

 and calculations which have been undertaken and executed is now in 

 ' ttie press, and will shortly be in the hands of the public. 

 ^ In the progress of these operations it has been found, on deter- 

 mining the most probable spheroid from all the astronomical and 

 'geodetic amplitudes in Great Britain, that the plumb-line is consider- 



