HORTICULTURE. 47 



ouly through experiments carried out on the farm and continued through several 

 years; and that such variety tests are an agricultural necessity. 



Tobacco, M. Popovici ( Tutuniil. lUicharvsi : F. (ilihl Fii, ISDti, pp. 13G,fi(j8. JS). — 

 This is a general treatise, giving the natural history of tobacco and the chemistry, 

 culture, technical treatment, fermentation, aud manufacture of extracts. 



Harvesting seed leaf tobacco crop (Amei: Agr. {mid. ed.) 5S (189G), No. 7, pp. 

 lU, 12.2). 



The hardness of the grain in the principal varieties of wheat, N. A. Cobb {Agl. 

 Gaz. X. S. Wales, 7 {1S90), No. r>, pp. ^79-298, figs. ^5).— Forty grains each of 54 

 varieties of wheat Avere tested for hardness for the crops of l>t93, 1894, and 189.^. 



A study of new forage plants, C and H. Dexaiffe {Plantes fourrageres nouveUes, 

 etude. Carignan: 1896, pp. 40). 



HOETICULTURE. 



Subirrigation in the greenhouse, W. J. Green and E. C. Green 



{Ohio Sta. BuJ. 01, pp. 57-7(1, pis. J). 



Synopsis. — This bulletin discusses the construction of greenhouse benches and beds 

 for subirrigation, tlie history of subirrigation, a comparison of surface and sub- 

 irrigation, aud the results of experiments in subirrigation. The latter is highly 

 recommended as the best method of greenhouse watering. Notes on the culture 

 of lettuce under glass are included. 



Ill tlie coustnictioii of greeiilionse benclies for subirrigation water- 

 tight beds are necessary. These may be made of boards with the 

 cracks battened and cement spread over the bottom to a depth of 

 about half an inch and 1 to 2 in. thick at the angle with the side- 

 boards. A better plan, however, is to construct the benches on racks 

 of gas pipe a few feet abov.e the ground, on which maybe laid bottoms 

 of tile, a size 12 b}^ 24 in. being recommended. The sides of the 

 benches may be made of ordinary roofing slate, 7 by 24 in., held in 

 place, as are the bottom tiles, by means of iron clips and cajis. After 

 the tile and slate are in place, cementing is to be done as in the case of 

 wooden benches. The irrigation tiles may be laid lengthwise or cross- 

 wise the beds; but if the runs are longer than 50 ft. there should be 

 from 1 to 2 in. fall in that distance. Two-and-a-half-inch drain tile are 

 considered cheapest and best, simjily placed end to end in rows 2J ft. 

 apart, and opening on the surface at the upper end, where Avater may 

 be ])oured in. To guard against a too rapid flow of water toward the 

 lower end, strips of tin should be inserted in the joints of tile at inter- 

 vals. From to 10 in. of soil has been found sufficient for most purposes. 



Thehistory of subirrigation in the greenhouse is briefly discussed, the 

 method, it is claimed, having been first tried at the Ohio Station. It 

 is stated that watering by subirrigation is more cheaply and efificientl.y 

 done than by the ordinary method, as both labor and water are saved and 

 the moistening of the earth is distributed more evenly. The difficulty 

 frequently met with in surface watering, due to the foliage of the plants 

 preventing thorough watering of the soil, is obviated by subirrigation, 



