344 EXPERIMENT STATION RECORD. 



In g-cneral, Ainericun varieties leave iimch to ]»e desired as regards 

 their resistaiiee to drought. European-Anieriean hytirids proved more 

 resistant than Amci'lean sorts. Some varieties of Kipai-ia proved quite 

 satisfactory. Rupestris suffered, especially in sandy soils. Berlandieri 

 of the American species proved most resistant to dryness, and this 

 quality was often found in its hybrids. 



A new substitute for rubber (ScL A7ner\,82 {1900), No. W,])jy. 309, 

 310). — It is reported that a substitute for rubber has been found in the 

 extract obtained l)y hydrocarbon solvents from the macerated wood of 

 a shrub growing- in Central Mexico, sometimes called yule, and having 

 the botanical name of '"'' Synathereoeas mexicanas.'''' 



"The shrub grows wild on the rolhng land and attains the average height of 3 ft. 

 ... It grows abundantly, may be easily cultivated, roots readily fi'om cuttings, may 

 be cut two or three times a year and immediately begins to grow, and shoots up again 

 to form new wood. It does not belong to the plants which yield milky juices, being 

 a comparatively hard wood and growing as a small scrubby bush, but there is found 

 Avithin its bark and wood a large amount of gummy matter, and upon comminuting 

 it by cutting finely, grinding, or pounding the same, and macerating it with a hydro- 

 carbon solvent, such as gasoline, naphtha, ether of petroleum, oil of turpentine, or the 

 like, this gum is softened and extracted from the wood, and when extracted does not 

 harden to crystallization, but still holding a small portion of the hydrocarbon remains 

 as a viscid sticky mass that fulfills all of the physical conditions of crude rubber. 

 It may be vulcanized perfectly, and is superior to most India rubber, since it is free 

 from all mechanical impurities, and needs no preliminary cracking, grinding, and 

 washing as does the ordinary crude rubber." 



The process of maceration is described. A jneld of 40 lbs. of gum, 

 having a density at 15° C. of 0.98, is reported for each 100 lbs. of the 

 shrub macerated. Its advantages over ordinary rubber are saving in 

 cost of reproducing the plant, exportation, material used in purifying 

 establishments, fuel. machiner3% and time. 



Plant breeding, D. R. Pillsbey {Florida Agr., 27 {1900), No. 38, pp. 561,562).— 

 Popular presentation of some results already obtained by plant breeding. 



Summary of the work of the horticultural division for the year 1899, S. T. 

 Mayxard iM(t!<mclivt^rtts Ilatcli Std. Bui. 06, p. 19). — Sunuuarized results ol)tained in 

 variety and fertilizer tests with orchard and small fruits and grapes are reported and 

 suggestions given on thinning fruits and the pruning of fruit trees and plants. A 

 sj^raying calendar concludes the bulletin. In the fertilizer tests with apples on sod, 

 marked improvement was observed only when nitrate of soda was used. 



Report of the assistant in horticulture, A. T. Jordan {New Jersey Stas. Rpt. 

 1899, pp. 131-187, pi. 1, dgm. 1) . — The fertilizer and irrigation work here reported 

 in detail with blackberries, raspberries, strawberries, currants, gooseberries, orchard 

 fruits, lettuce, and tomatoes is in continuation of similar work reported in 1898 (E.' 

 S. R., 11, p. 735), and has been abstracted from another source (E. S. R., 11, p. 1039) . 

 Articles included in these pages on pear growing in New Jersey and on forcing toma- 

 toes have also been noted ( E. S. R. , 12, pp. 144, 146) . In experiments with lettuce, rad- 

 ishes were grown between the rows and subject to the same conditions of soil, irriga- 

 tion, and fertilizers. With this crop, surface irrigation proved better than subirrigation, 

 and benches seem to have given better results than solid beds. Lime added to a good 

 forcing soil resulted in considerably decreasing the yield of radishes, while nitrate of 

 soda on the same soilin the absence of mineral fertilizers decidedly increased the yield. 



