J O I 



216 



I O N 



Joinery, 



Joinvillc. 



Fig. 1. 

 No. 3. & 4. 



Fig. 1. 

 No. 5. 



a q b equal to the quadrant AB, No. 1. and draw a v a 

 tangent to the arc a q b at a, and make a v equal to a v, 

 No. 2. and the arc a a equal to the straight line AQ, 

 No. 2. Draw the radii a z and b z, which will be a 

 right-angle. Draw v v parallel to a z. Make v ' equal 

 to the breadth of the rail, as shewn by the plan, No. 1. ; 

 and draw the concave side of the plan v' a' q' />'. Then, 

 having the seats of three points v, q, it', and the heights 

 VVV, QH and BX in No. 2. we may now proceed to 

 find the face mould in the same manner as in find- 

 ing 1 the section of a cylinder, Fig. 1. and 2. ; viz. draw 

 the chord b' v', and draw v tv, qr, and b' x perpendicu- 

 lar to b v. Make v tv, q r, and b' x respectively equal to 

 VVV, QR, and BX, No. 2. Join x tv and b' v, and pro- 

 duce them to meet each other in s, and join x s. Draw 

 r i parallel to x s, and q i parallel to b' s. Join s i, and 

 produce b' v' and i s to meet in f, and join xf; and 

 proceed to complete the face mould which is the sec- 

 tion of a cylinder, in the same* manner as in Fig. 1. 

 and 2. as is plain by the small letters instead of the 

 large ones. 



No. 4. Shews the construction of the face mould for 

 the upper part of the circle, which is the same as in 

 No. 3. only the heights must be taken downwards, and 

 from the lower side of the falling mould. 



No. 5. Shews the application of the face mould to 

 the plank, according to the following description. This 

 diagram exhibits the two sides and the edge of the 

 plank sketched out in one plane, as shewn for the cir- 

 cular sash-frame in a circular wall. W is the plane of 

 the top of the plank, X that of the edge, and Y the 

 under face of the same. Previous to commencing the 

 operation of cutting out the rail, the plank must be first 

 bevelled on the edge. In this case, for the lower piece, 

 it must be taken off the under edge, according to the 

 angle b' n h, No. 3. ; that is, the two planes W and X 

 must form an acute angle equal to the angle b' n h. 

 Place the face mould No. 3. upon the plane W, and make 

 the chord line coincident with the edge AB, that is, the 

 extremities of the concave edge to AB. Draw c d on 

 the edge of the plank, making the angle B c d equal 

 to the angle J'x b', No. 3. Having drawn the lines on 

 the top, round the face mould, apply the same point 

 that was at c to d on the other side, and bring the chord 

 to coincide with the edge CD. Then the plane of the 

 mould coinciding with the plane of the plank, draw 

 lines on the plank round the edges of the face mould 

 as before. The lines being thus drawn, the superfluous 

 parts that were on both sides of the mould are to be 

 cut away, in such a manner as to form the surfaces of 

 a cylinder on both sides. The falling mould construct- 

 ed at No. 2. must be bent upon the convex side, and 

 lines drawn upon that side round the edges of the fall- 

 ing mould. The superfluous wood must be cut off 

 from the top of the piece, according to the upper line, 

 by means of a square or right-angle ; but, in squaring, 

 the edge of the stock of the square must be always 

 placed parallel to the axis of the cylinder. The other 

 edge will be found by guaging the piece to its thick- 

 ness on both sides, which is generally about two inches. 



JOINVILLE is a town of France, and principal 

 place of a district in the department of the Upper 

 Marne. The town is situated on the Marne, and con- 

 tains several good houses, and some streets that are to- 

 lerably wide. The church, which is an old building, 

 is a mixture of Greek, Gothic, and Norman architec- 

 ture. It has a handsome spire, all the ornaments of 

 which, and even the pillars, are covered with slate. 

 At the north end of the town, there is a neat bridge of 



three arches over the Marne, and there 13 a fine mall of 

 trees near it, on the banks gf the river. A canal passes 

 through the town. The town contains 700 Tiouses, and 

 3086 inhabitants. 



ION A, ICOLMKILL, I-COLUMB-KILL, more correctly 

 Y or I, is a celebrated island of the Hebrides, situated 

 on the south-west sideof the island of Mull, from which 

 it is divided by a channel half a mile wide By Bede, 

 who is believed to have died in the year 70'2, it is named 

 Hii, or Hy, for the punctuation of vowels had not then 

 been introduced ; and in the annals of Ulster, which 

 are of later date, it receives the designation of lae and 

 Aoi. However, in the records of Scotland down to 

 the middle of the 16th century, in inscriptions contem- 

 porary with that period, still to be seen upon the island, 

 and by the neighbouring inhabitants, it is simply called 

 Y or I. This is said by etymologists to be the Irish for 

 island ; that I was" aspirated by Bede to H'y ; and 

 I-tfion, also the Irish for the island of waves, being pro- 

 nounced /-on, was by the monks readily latinized 

 Hyona. lona likewise appears on monumental inscrip- 

 tions a little anterior to the Reformation ; but that 

 name is now entirely lost in the neighbourhood. By 

 some of the ancient Irish and Danish writers, it is de- 

 signed the Holy Island; and its modern appellation 

 Icolmkill signifies the island of the cell of St. Columba, 

 which does not seem to have been unknown to Bede. 



This island is two miles and a half in length, by lit- 

 tle more than a mile in breadth, and contains a super- 

 ficial area of about 1300 Scotch acres. The surface is 

 unequal, rising into eminences ; and the most elevated 

 part is about 400 feet above the level of the sea. A 

 light sandy soil prevails. Upwards of 500 acres are in 

 occasional cultivation, and afford abundant crops of 

 barley and oats, besides which, the pasture of the 

 island is celebrated all over the vicinity. Notwith- 

 standing the lateness of sowing the grain, harvest is 

 early in August. Adamnan relates, that barley sown 

 in June, by command of Columba, ripened in the be- 

 ginning of August, which, however, he ascribes to a 

 miracle; and he alludes to the abundance of fruit. 

 Great variety of beautiful and valuable minerals are 

 found on Icolmkill, among which are a small vein of 

 coal ; and Mr. Raspe observed an efflorescence of cop- 

 per. Fine white marble, semi-pellucid when reduced 

 to a thin plate, exists in strata of some thickness. It 

 cuts freely, receives a good polish, and, except for the 

 loss of colour, which is converted to a yellowish cast, 

 resists the action of time. There are extensive rocks of 

 sienite on the south-west shore, which will afford blocks 

 of any dimensions, of vivid colour, extremely hard, and 

 susceptible of a high polish. Of this substance all the 

 remnants of antiquity, of which she shall immediately 

 treat, are constructed. Rocks of beautiful serpentine 

 also stretch along the southern extremity, of consider- 

 able hardness, an agreeable green clouded with .other 

 colours, and suitable for slabs or sculptures. Its quali- 

 ty has been compared to that of the ancient serpentine, 

 but although masses of large dimensions might be pro- 

 cured, "it would not be without much labour, on ac- 

 count of the solidity of the rocks. In the Port-na- 

 curaich, a creek where Columba landed, there are found 

 nodules of nephriticus, called the Port-na-curaich stone, 

 from the size of a pea to that of an apple. These are 

 of a green colour, of a smooth soft appearance when 

 polished, and are made into trinkets of various kinds. 

 Many are worn by the Hebrideans as amulets, some- 

 times set in silver. They believe that a certain charm 

 attends their presence, and they say that their colour 



lona, 



