1 74 Proceedings. 



nuts yield a valuable oil, and the wood is hard, and useful for many domestic 

 purposes. 



" I have the honor, &c. &c." 



A quantity of seeds have been left at the Museum for distribution, and persons 

 desirous of cultivating them, and disposed to furnish a report of their success or 

 otherwise, may obtain a portion on application. 



His Excellency laid upon the table a pamphlet by Professor Piazzi Smyth, " On 

 Raising Water for the purposes of Irrigation in the Colonies." 



Tables of Meteorological Observations made at G-overnment House by Messrs. 

 HuU and Dobson, for the three months ending 31st March last, were also laid 

 before the meeting. 



Sir William Denison then read a Report from Major Cotton, (embodying a 

 brief Report from Mr. Sprent), upon the Trigonometrical Sm-vey of Van Diemen's 

 Land, now in progress. The original base line measured at Ralph's Bay extended 

 to 20,181-635 feet, or nearly four miles; the line of verification which was subse- 

 quently measured at Norfolk Plains extended to 25745-7 feet; the length of this, 

 computed fi-om a series of 33 triangles, extending to a distance of more than 100 

 miles, being 25,746-0 feet, exhibits an approximation so close as to be scarcely 

 credible, the difference being only about Zk inches. His Excellency the President 

 remarked that the correspondence was so remarkable as to have created in his mind, 

 first, cm-iosity ; and then, some doubt of the absolute accuracy of the calculations ; 

 and that to satisfy himself he had worked through the calculations and proved 

 the acciu-acy of the results. 



The observations at the main stations were taken by Mr. Sprent with a 12-inch 

 altitude and azimuth instrument, and at the secondary stations with an 8-inch 

 theodolite. 



The rods used in the measurement of the base lines, 15 feet in length by 2 inches 

 square, were made in 1849, in damp weather, of old Baltic fir, satm'ated with 

 boiling oil, varnished, rolled in flannel, packed in saw-dust, in cofiers 6 inches 

 square, closed at the ends, but leaving room for the rods to expand. To the ends 

 of the rods, which were supported centricaUy in the cofiers by blocks of wood, were 

 attached brass caps rising to the upper surface of the coffer, and bearing vernier 

 scales, by which theu' lengths were determined to the 400th part of an inch, 

 agreeable to the only standard measure then in the colony, a 4-feet steel measure 

 divided into inches and fortieths. The rods have been measured fi-om time to 

 time since without exhibiting any appreciable difference. The original base line 

 has been measured three, times — once in 1849 and twice in 1851, and the length 

 assumed is the mean of the two last, which differ only .85 feet from the first, — a 

 discrepancy owing probably to the comparatively imperfect nature of the indi- 

 cating scale, which at the time of the last measurements had been improved, so as 

 to read with precision to the 5000th part of a foot. His Excellency the President 

 observed that the colony already possessed upwards of thirty principal stations, 

 ■whose relative position is absolutely determined within a few inches in any case, 



