DISKASE8 OF PLANTS. 77") 



Coast for the years 1880 to 1 903, inclusive, and of the results of experiments in grow- 

 ing exotic rubbers. 



The quantity of rubber exported from the Gold Coast has decreased from the maxi- 

 mum production in L898 of 5,984,984 lbs. to 2,258,981 lbs. in L903. A number of 

 species of foreign rubbers have been grow n in the botanic gardens of Aburi. Of these, 

 Heoea bragiliensis has given the best results, considerably surpassing in yield and 

 quality of rubber the native Funtumia elastica. 



The experiments indicate thai trees of /•'. elastica should nol be tapped before thej 

 are 9 years old. Trees of H.brasiliensis, 10 years old, yielded on an average l lb. \ oz. 

 per tree, while the largest yield from trees of F. elastica, 7 to 9 years old, was I oz. 

 Not only does //. brasUiensis grow faster than /•'. elastica and yield a larger amounl 

 of rubber of better quality, but it is also freer from insect pests and fungus attacks. 



Investigations of kickxia caoutchouc from Cameroons (Tropenpflanzer, 9 

 (1905), No. 10, />. 590). Analysis of the caoutchouc from this plant showed 3.5 per 



cent water, s 7 2 percent best quality caoutchouc, 0.5 percent | rquality caoutchouc; 



7. 1 per cent caoutchouc resin, and L. 7 sand, etc. 



Hand book of timber preservation, S. M. Rqwe I Chicago: Pettibone, Sawteli <v 

 Co., 1904, souvenir ed., rev., PP- '"- : IV, pU. ?0,figs. 58). -The methods, appliances, 

 ami materials used for preserving timber on a large scale are discussed at length 

 for various woods, many illustrations being given of the appliances used in preparing 

 the material and applying the preservatives. 



A new impregnation treatment for wood, <J. Jane a (Centbl. Gesam. Forstw., 

 81 (1905), No. tO, pp. 897-401). — The Etuping system of timber preservation is 

 described. 



In the case of railroad ties, the ties are first submitted to a pressure of 5 atmos- 

 pheres. While still under this pressure they are immersed in coal tar oil and the 

 pressure gradually raised according to the character of the timber to a maximum of 

 15 atmospheres. The oil is then drawn off and the release of pressure facilitates the 

 driving out of much of the oil that entered the wood. 



It is claimed that where 36 kg. were formerly necessary for impregnating a sleeper 



having 0.11 CU. meter content hut 5.5 kg. are required by the Etliping system. It is 

 estimated that the German railroads use annually about 200,000 tons of coal tar oil 

 as a preservative for railroad ties, and that under the Ettiping system but 30,000 tons 

 will be required. 



Turning- sawmill waste into water-white turpentine (Fla. Twnes-Union, 1905, 

 Oct. 97, p. 6). — A description isgivenof a successful commercial plant for extract- 

 ing water-white turpentine from sawdust by means of retorts into which steam is 

 injected. It is claimed that from 5 to L5 gal. of water-white turpentine can be 

 obtained by this process in less than an hour from l' tons of sawdust. 



DISEASES OF PLANTS. 



Fungus diseases in India in 1903, E. .1. Butleb (Ztschr. Pfianzenkrank., 15 

 (190.5), No. i, />/>. ;; f8). — A condensed account is given of the parasitic fungi 

 observed on a number of economic plants in India during L903. These are grouped 

 according to host plants into diseases of cereals and fodder plants, vegetables, sugar 



cane, tea and coffee, palm-, forest trees, etc. 



Among the principal diseases of cereal.- the author note- the occurrence of a num- 

 ber of species of rusts and smuts, and for the prevention of the latter he suggests 



soaking the seed preliminary to Bowing in a \ per cent solution of copper sulphate. 



A wilt disease of pigeon pea, due to the fungus Neocosmospora vasinfecta, is reported 

 as quite common wherever this plant is cultivated. The esrly and late blight of 

 potatoes are prevalent, and a disease ol eggplants, due to an undetermined species of 

 Oolletotrichum, is reported, 



