446 The Romsey Observatoi'y. 



reach from centre to centre of the posts, and these twelve 

 pieces, four inches "wide, must be nailed on their tops. 



The walls of the house must now be made by nailing 

 weather-boards on the inner sides of all the posts, beginning 

 at the upper part, and only leaving the apertures for the door 

 and windows. 



The bearers for the floor can be laid next ; they consist of 

 slabs of any kind of timber with their smooth sides up. Sup- 

 posing the brick or stone pedestal for the telescope to be two 

 feet in diameter, these slabs will be four feet long ; they may 

 be supported on logs of wood, or any other blocks, so that the 

 floor when laid upon them is one foot above the ground. Care 

 must be taken that neither they nor the boards touch the 

 pedestal. 



The ground plan shows the arrangement of the boards, five 

 of the spaces being left open in the drawing to show the 

 bearers. 



The door and windows can be made according to the taste 

 of the builder, but simple and neat cases for them can be 

 formed by nailing inch board, planed, against the rough posts. 

 Very simple frames for the windows, with one large square of 

 glass in each, look quite as well as casement, and are very 

 cheap. 



The next part is the roof, which is constructed as follows : 

 — Twenty-four pieces of inch plank, about six inches wide and 

 between two and three feet long, are so cut that twelve of them 

 shall form a circle ten feet three inches wide at its inner edge ; 

 these being laid out in a true circle, marked in chalk upon a 

 flat floor, the other twelve are laid upon them, crossing the 

 joints ; they are then all nailed together and clinched. The 

 inner edge is then made to a true circle, and smoothed with a 

 compass plane. 



Next the rafters must be cut, twelve or twenty-four in 

 number, or intermediate as best suits the canvas. The Eomsey 

 Observatory has twenty-four ; they are seven feet six inches 

 long, and two by one inch thick. Being cut to the right bevel, 

 their feet are simply nailed down to the great wooden ring 

 above described ; their upper ends meet on a block surmounted 

 by a knob. 



Strong canvas is now to be nailed with tinned tacks upon 

 the rafters. A space will be left in the roof nearly six feet 

 wide, wherein no rafters arc lixed. It is the opening for the 

 telescope, and is closed wilh shutters in this way: — Suppose 

 I In' number of rafters be only twelve, then tiro triangular 

 frames of the same wood, each comprising one-twelfth part of 

 the cone, will be hinged to the contiguous rafters on each side, 

 and the canvas nailed over the joints. A broad thin strip of 



