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An Account of the Trigonometrical Survey, carried on in the Years 

 1797, 1798, and 1799, by Order of Marquis Cornwallis, Master- 

 General of the Ordnance. By Captain William Mudge, of the 

 Royal Artillery, F.R.S. Communicated by His Grace the Duke of 

 Richmond, F.R.S. Read July 3, 1800. [Phil. Trans. 1800, p. 539.] 



The mode of conducting this important survey having been already 

 noticed in the Journals of the Society on various former occasions, it 

 will only be necessary here to state the progress of the operation, 

 which we find has now been carried on over Essex, the western part 

 of Kent, Suffolk, and Hertfordshire, and portions of the counties con- 

 tiguous to them. A distinct section contains the calculations of the 

 sides of the principal and secondary triangles extended over the 

 country in the three abovementioned years, together with an account 

 of the measurement of a new base-line on Sedgemoor, and a short 

 historical narrative of each year's operations. Another section con- 

 tains the computed latitudes and longitudes of the places on the 

 western coast intersected in 1795 and 1796, and also of such others 

 since determined as lie conveniently situated to the newly observed 

 meridians. Here we find likewise the directions of those meridians; 

 one on Blackdown in Dorsetshire, another on Butterton Hill in De- 

 vonshire, and another on St. Agnes Beacon in Cornwall ; as also the 

 bearings, distances, &c. of the stations and intersected objects from 

 .the several ascertained parallels and meridians. 



The Croonian Lecture. On the Irritability of Nerves. By Everard 

 Home, Esq. F.R.S. Read Nov. 20, 1800. [Phil. Trans. 1801, p.I.] 



Its object is principally to investigate the opinion hitherto enter- 

 tained, that the nerves may be considered as chords that have no power 

 of contraction within themselves, but only serve as a medium by 

 means of which the influence of the brain may be communicated to 

 the muscles, and the impressions made upon the different parts of 

 the body may be conveyed to the brain. After pointing out the ex- 

 treme difficulty of such an inquiry, owing to the few opportunities 

 that offer for investigating the real state of the nerves in the living 

 body, Mr. Home intimates that he resolved to avail himself of every 

 opportunity that might offer of any operation in surgery performed 

 upon nerves, either in a healthy state, or under the influence of dis- 

 ease, in order to elucidate this intricate point, without neglecting 

 certain experiments he thought he could devise upon animal bodies, 

 before they are wholly deprived of life. 



The first case, which explains some circumstances respecting the 

 actions of the nerves when under the influence of disease, was that 

 of a middle-aged person, who, having hurt his thumb by a fall, expe- 

 rienced long after an occasional swelling and convulsions in that part, 

 attended with spasms, which at times extended in the direct course 

 of the trunks of the radial nerve up to the head, the patient being at 

 times afflicted with absolute insensibility. In order to put a stop to 

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