This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
This has already been referred to in Vol. II, p. 14. The flowers are used for colouring butter, flavouring soups, etc. Between June and September they are gathered and hung up in the shade to dry slowly, after which they are stored for winter use.