1839.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



113 



sc= 



A -paper was also read, entitled, ' Some Jrrotml of fhe Hurricane of the llli of 

 January, 1839, as if was expericutvti in the nait/hbourhood of Duiu/rii-e,' in a li-lh'r 

 aihlresxid lo P. M. RoGET, M.D.,Si.c. T^.S,, by P. Garden, Esq. 



After describing the position of his house, and the iiiitnre of the instruments 

 employed for observation, the writer gives his observations of the barometer 

 and tiierniometer on the tiih and 7 of January last, and proceeds to state, 

 that on the 6th, at about ten minutes past ten o'clock, p.m., violent siiuulls 

 eonimenoed, at first with intei"missions of perfect calms, but gradually becoming 

 more frecjnent, and being accompanied by the sound of sti'ong and increasing 

 whirlwinds. By eleven o'clock, the wind was observed to proceed from the 

 east, and its velocity was estimated at forty miles an hour. Its violence then 

 increased, and threatened to blow down the chimneys. At midnight it abated, 

 at the same time shifting to the south or west. At two o'clock in the morn- 

 ing, nearly two tons of lead were torn away by the wind from the west-end 

 platform on the house-top, and thrown down behind the house in a westerly 

 direction. Some of the lower windows having been left a little open, the 

 wind thus admitted into the house forced up and blew off the very heavy 

 hatch door of the roof, which was covered with lead. The whole house rocked 

 terribly, and even the stone floor of the half sunk kite-hen story heaved as if 

 shaken by an earthnuake ; the slates from tlie roof were blown in every 

 direction, some being carried to a prodigious distance. During the greater 

 part of tlie night the rain fell in tremendous torrents. In the interval from 

 two to lialf-past three in the njorning, the barometer sunk very nearly an inch 

 and a half, and reached its greatest dejiression. But the tempest continued 

 till about four o'clock, when it began grailually to subside. Extensive devas- 

 tation occurred among the trees ; some that were blown down raising two or 

 three tons of clay soil with the roots. Several trees thus thrown down fell 

 with their tops to the W.N.W. The writer concludes, from these and either 

 observations, that the first and squally part of the storm began from the 

 E.S.E., and blew from S. by W. at about midnight, and that most injury was 

 done to the slatitig and roof when the wind was nnt far from the south. It 

 then gradually veered to the west, till noon, and reached the N.W. point by 

 eight o'clock in the evening of the same day. 



Feb. 21. — J. G. Children, Esq., V.P., in the chair. 



Captain Arthur Conolly, and Lieut. -Col. W. Reid, C. B., were elected fel- 

 lows of the Society. 



The following papers were read : — 



I. 'An Account of the Processes employed in Photogenic Drawing,' in a 

 letter to S. H Christie, Esq., Sec. R.S., by "H. Fox Talbot, Esq., F.R.S. 



2.-' A Description of an Hydro-pneumatic Baroscope,' by T. J. Cooper, Esq. 



3. Continuation of Mr. Darwin's paper ' On the Parallel Roads of Glen 

 Roy, and other parts of Lochabar.' 



THE ROYAL IRISH ACADEMY. 



Jantja'by 14, 1839.— Sir W. R. Hamilton, A.M., President, in the Chair. 



His (irace the Archbishop of Dublin, V.P., having taken the chair j<ro 

 trmporc, the President communicated U, the academy the first part of his 

 researches on the Dynamics of Light. 



WiLi-iAM Bald, Esq., Civil Engineer, read a paper entitled " An Account of ihc 

 tSnrvey and Map of the County of Mayu." 



The author commenced by giving a brief account of the origin and pro- 

 gress of the construction of topographical maps in Europe. In modern limes, 

 the first attempt at the construction of topographical maps may be dated from 

 the seventeenth century, and was due to the Swedes. Under Charles the 

 Ninth, a surveying department was organised, placed luider the direction of 

 Buneus, and particularly encovu'aged by Adolphus. In lOSl, the Swedes 

 had completed the general topographical map of Sweden ; but it was kept 

 secret, and at the end of a century, they had only published some parts of it. 

 These maps were consti'ucted for the purpose of ameliorating the condition 

 of several provinces of the kingdom, which had been desolated by war. The 

 Dutch also connnenced early to construct topographical maps. 



The measurement of many arcs of the meridian to determine the figure of 

 the earth, had very much extended geodetical operations, and had, in many 

 cases, become the elements on which topographical maps were based. The 

 numerous geodetical surveys called into activity the inventive powers of the 

 ablest artists in Europe, and instruments of exlieme accuracy were pro- 

 duced ; and the skill of observing and determining angles kept pace w ilh 

 those improvements connected with this important brandi of science. The 

 repeating principle due to the celebrated Tobias Meyer, gave birth to Borda's 

 circle of repetition about 1789, an instrument which has been connected with 

 the most brilliant scientific operations which adorn the annals of tlie eighteenth 

 century. 



Mr. Bald then showed to the academy some specimens of the new map of 

 France, and noticed briefly the trigonometrical survey of England — the 

 Down survey of Ireland — the maritime surveys of Ireland — the county sur- 

 veys, and the bog surveys. He made some observations on the great import- 

 ance of accurate maps, especially to professional men engaged in conducting 

 public works, .such as roads, canals, river navigations, harbours, railways, 

 supplying towns with water, irrigations ; to the geologist and miner, exploring 

 the strata, and mineral wealth of the coinitry ; to the statesman devising im- 

 provements, and developing its resources ; and to the poor, by affording use- 

 ful employment to the working classes. 



The author then alluded to the map of Esyi'h which was made duruig the 



period it was under the dominion of the French republic, and which received 

 from Bonaparte all that protection and assistance, which so much distin- 

 guished him on all occasions regarding the advancement of the works of 

 science. This map was engraved on fifty-three sheets of copper, and the 

 names are engraved both in Arabic and French. 



After this introductory account of the rise and present state of the topo ■ 

 graphical art, Mr. Bald i)roceeded to the details connected with the suney 

 of Mayo. 



The instruments used in this survey were a seven inch theodolite ; two 

 five-inch theodolites, by Troughton ; a small theodolite, by Dollond ; and 

 also a five-inch one by the same artist. In taking the levels over the bogs, 

 two of Troughton's best levels were used. The barometers were made by Mr. 

 TiKtmas Jones, of London. There were also two plain tables, a chain for 

 measuringjbase lines, a sextant four inches radius, and two sextants, each ten 

 inches radivis, divided to ten seconds for observing altitudes, one of which was 

 made by Troughton. 



The proceedings of the geometrical details of the survey were then given, 

 and the mode of describing the rise and fall of the ground, which was shaded 

 on the map with a depth of colour corresponding to the sines of the angles of 

 inclination. The irregularities of surfaces were simply delineated by hatch- 

 ing lines, drawn in the direction of the declivities, forming a series of nor- 

 mals, perpendicular to the horizontal lines of equal level. 



Dit. Smith read a paper (by LieotenXnt Nkwenham, II. \.) " On a Tumulus or 

 Barrow, near Rush, County of Duhliu.'* 



The barrow, called Knocklea, or the Giant's Hill, is situated on the edge 

 of the cliff, about midway between the village of Rush, county of Dublin, and 

 the martello tower to the northward, called Dronianick, and immediately in 

 front of Sir William Palmer's residence, Kinure Park. 



It appears to have been composed of quantities of bonlder stones and earth 

 heaped up into a conical form, and sloping away to the base, which was 

 square, as appears from the eastern angle, which yet remains perfect. Within 

 the base of the mound there was a circle formed of large stones placed on 

 their ends, and about one hundred paces in circumference. 



The farmer who rents the land on which it stands has removed about one- 

 half of the mound, for the sake of the earth as a manure, and nearly one- 

 half of the circle of stones on the south side, for the purpose of building a 

 wall, part of which is erected on the stones tbnniug the western side of the 

 circle. In the course of his depredations he discovered a passage which 

 opened on the south side;* its entrance was funnel-shaped, and the walls of 

 this passage were formed of flagstones placed on their ends, and roofed in 

 with the same. It was about eleven yards long, and one in width; and led 

 to a low chamber about eight feet long, and six wide, which was situated 

 nearly in the centre of the liarrow, and formed of stones in the same manner 

 as the passage. 



The farmer removed all the stones forming the western side of the passage, 

 and in the course of his excavations found some human bones on the south 

 side of the chamber, and within the circle of stones. The lines of stones 

 foiming the sides of the passage appear to continue on through the mound 

 towards the north side ; and a few feet below the present surface of the bar- 

 row, a little to the north of the chamber, there is a bed of periwinkle shells, 

 about eight inches thick, with some limpet and muscle shell? intermixed ; 

 and beneath this bed of shells there is a cjuantity of rich daric mould, with 

 some reddish earth, which has the appearauo" of being burned. A few 

 human bones, and some bones of small anim;i'.«, ivcre fourjd in the earth 

 beneath. 



Outside the circle of stones, and on the very edge of the cliff, near the 

 western angle of the mound, there was foinid a rudely -forn".ed*f.;ra'-i contain- 

 ing a human skull, with the bones of the arm, leg, and thigh, which appa- 

 rently had never been disturbed ; the bones of the back, ribs, &c., could not 

 be discovered. 



Tliere are several remains of entrenchments and smaller mounds in the 

 neighbourhood. 



Circles of stones arc found enclosing many similar barrows in Ireland. 

 At New Grange, near Dowth, in the county of Louth, the circumference of 

 one measured about four hundred paces ; and in a barrow near Drogheda, 

 an engineer oflicer found a gigantic skeleton, a pair of elks' horns, and a 

 spear, in an upright position : the h(:)rns were above the skeleton. There are 

 many barrows in the neighbourhood of Drogheda, which, if opened under 

 the direction of competent persons, would probably lead to many very inter- 

 esting discoveries. 



The President gave an account of a singular appearance of the clouds, 

 observed on the 16th of December, 1838, at the Ohservatoi-y of Trinity Col 

 lege, Dunsink. They appeared, for at least the last four hours of day-lighl, 

 to be arranged in arches which converged very exactly to the N.E. and S.W. 

 points of the horizon ; while the breaks or joints in these arches were directed, 

 though with less exactness, to two other horizontal points, which seemed to 

 be always opposite to each other, but ranged from N.W. and S.E. to N. and S. 

 Conjectures were ofl'ered with respect to the cause of this appearance. 



SCHOOL OF DESIGN, 



MARGARET-STREET, CAVENDISH -SIJUARE. 



Wc arc happy to witness the progress of this excellent institution, which 

 under ils able conductor, Mr. A. de Villalobos, seems to effect all the purposes 



• Mr. Newenham thinks that, as f»r as liis Observation ha8 extended, the entrance 

 of all bariDW) is on th« south side. 



