294 THE FRUIT GROWER'S GUIDE. 



be continued for about two months, or till the growth is ripe and the leaves commence 

 falling. 



Muscat of Alexandria and all the shy-setting grapes require a somewhat high 

 temperature at the flowering period, say 5 more than for Black Hamburgh ; and all 

 late grapes need a moderately high temperature to be continued for a longer season 

 than other varieties. After the stoning is completed say, early in July there should 

 be a natural rise of 10 higher than the maximum advised, namely, 80 during 

 stoning, and with free ventilation it will enlarge the berries. 



Ventilation. The admission of air in the case of early forced houses up to the 

 time of the vines flowering is only for the prevention of too high a temperature, and 

 there is generally a sufficient interchange of air between the laps of the glass to sustain 

 healthy growth. When the inside and outside temperatures are nearly the same, as 

 occurs in mild, dull weather later in the season, the air becomes almost stationary, and it 

 is then advisable to use a little extra fire and ventilation to effect a change of air daily. 

 During the flowering period, and after colouring has commenced, a "chink" of air is 

 necessary constantly, especially in houses with large panes of glass and close laps, 

 and it is important to increase the ventilation early and gradually, to prevent the 

 temperature rising to a dangerous height when the sun shines powerfully. The 

 ventilators should be opened on the side opposite to that from which the wind comes, 

 when it is rough and cold. The point to remember is this admit air early, and 

 let the rise of temperature nearly all take place afterwards. Those not experienced 

 in the management of vineries should admit a little air as soon as the sun touches the 

 glass ; then if the heat rises give a little more. Watch the thermometer, and as the 

 temperature increases admit more air, till the amount required for the day is reached. 

 Difficulties in ventilation arise during alternate sunshine and cloud. The weather 

 should as far as possible be anticipated, and the air reduced a little before rather 

 than after the obscuration of the sun if it is likely to be clouded for some time ; 

 and it is necessary to be on the alert when the clouds diminish, so as to be slightly in 

 advance of the sunshine in re -opening. In extremely changeable weather it is best not 

 to aim at a high temperature during the early part of the day, but merely keep a safe 

 one, and then, unless the vines are in flower or the grapes colouring, close early in the 

 afternoon, and allow the highest temperature which is considered safe. If by accident 

 or neglect the temperature rises too high before air is admitted, it must on no account 

 be lowered by full ventilation, but air should only be admitted to prevent a further rise, 



