They bloom about March or April in the open air.
An overflow is provided, discharging into the open air to allow the water to escape should the ball valve become defective.
In many gardens open-air tanks have been fitted up with hot-water pipes running through them to keep the water sufficiently warm in severe weather.
The open-air water-lily tank in the Royal gardens, Kew, is one of the latest and most up-to-date in construction.
Open-air conventicles were held in all parts of the provinces, and the fierce Calvinist preachers raised the religious excitement of their hearers to such aitch that it found vent in a furious outburst The lcono- P oasts.