THE WOODWORK. 71 
I always allow a bare j;in. “play” only, and find this 
answers admirably. The gauge should always be used again 
when nailing or screwing the bars to the purline, or vice 
versa, and take care that the former are fixed straight. 
Houses of any considerable size ought always to be fitted 
with gearing of some kind, to avcid the immense amount 
of time otherwise occupied in opening and closing the 
numerous ventilators. Several descriptions of gearing 
are now manufactured, but at once the simplest, most 
easily worked, and best, is Paine’s Counterbalance gearing, 
which is, moreover, by no means expensive. With this 
all the ventilators in one row are opened and closed 
simultaneously by means of a length of ordinary in. 
or lin. gas barrel, firmly screwed together and working 
in proper cast brackets, or carriages, screwed to the rafters 
or uprights. On to this are firmly keyed the levers, each 
with its connecting rod, to actuate each ventilator, and 
at intervals other short levers, each carrying a heavy cast 
iron weight, are fixed in such a manner as to counterbalance 
the weight of the lights completely, and thus enable them 
to be opened or closed with the greatest ease. The rod 
is worked by means of a toothed wheel and worm, which 
may be placed at either end, or in the centre of a long 
house, and is actuated by means of a rod and hand wheel 
fixed in any convenient spot. 
Gutters.—These are referred to now, because, in some 
cases, they enter in part into the construction of a house, 
or houses, as will be seen presently. Gutters of some kind 
ought always to be provided, for not only is a plentiful 
supply of rain-water at all times useful, but this, being 
perfectly pure, is invaluable in good  plant-growing, 
