Developed from around the 1850s in the Paris area and mainly used for the growing of salad and related crops. It was intensive both in terms of using relatively small amounts of land to grow large amounts of crops, all year round and intensive as far as labour was concerned. Whole books have been written on the subject and well as its introduction into the UK. The system was essentially targeted at the professional, particularly the market gardener; therefore set-up and running costs were both high, well out of the range of the normal amateur gardener. However, by the beginning of the twentieth century adoption by amateur gardeners in the UK was rising to such an extent that the firm introduced a series of frames and lights compatible with the French system. The frames were constructed of 1¼in. boards and very low off the ground, 9in. high and the back and 7in at the front. The lights had styles and top rails made of 2in. x 2½in., with 3in. x 1in bottom rails and 2in. x 1½in. bars. The frames were capable of being joined together by a method that required neither bolts nor wedges. The frames and lights were available either unpainted and unglazed or painted with one coat and glazed with 21oz. glass. The lights (3ft. 10in. by 4ft. approx.) were available either separately or as a complete unit with the frames. The combined frame and light/s were available in 1-, 2- or 3-light versions, measuring 4ft. x 4ft. 6in., 8ft. x 4ft. 6in. and 12ft. x 4ft. 6in. respectively.