Vol, XI. No. 277. 



THE AGRICULTURAL NEWS. 



399 



preservatives. The average losses of circumference were 0"10 

 inch anfl 027 inch, and the per cent, affected with decay 30 

 and 'Z'), respectively. 



The poles brush-treated with two coats of preservative 

 sold as creolin and those similarly treated with one coat of 

 preservative sold as wood creasote showed but slight 

 difference in loss of circumference at the ground line, the 

 average loss being 042 and 043 inch, and the per cent, 

 affected with decay 69"8 and 95 2, respectively. 



The poles brush-treated, respectively, with one coat of 

 preservative sold as creolin and (^oal-tar, showed a loss of 

 circumference at the ground line of 0'89 and 095 inch, and 

 a per cent, affected with decay of 100 and 98, respectively. 

 The loss with these poles was nearly as great as with the 

 untreated. 



The untreated poles were practically all more or less 

 affected with decay at the ground line, the average loss of 

 circumference for those seasoned prior to placement being 

 101 inches, and for those placed green 1'16 inches. That two 

 of those seasoned prior to placement showed no decay at or 

 near the ground line is possibly due to the fact that they 

 were both set on a hillside or slope where the drainage was 

 excellent. One of them was set in broken stone or rock. 



A second independent set of experiments gave the 

 following additional results: — 



The untreated poles set in crushed stone showed less 

 decay at the ground line than similar poles set in sand, the 

 average loss of circumference at that point being 1 77 inches 

 and 227 inches, respectively. 



The poles with charred butts showed less decay at the 

 ground line than similar uncharred and untreated poles set 

 in either crushed stone or sand, their average loss in circum- 

 ference at the ground being only 0'7 1 inch. 



RADIUM AND PLANTS. 



The influence of radioactive substances on plants 

 has received attention in the Agricultural iVeu'-s 

 (Vols. X, p. 183; XI, p. 363). The following note con- 

 cerning the action of radium itself is taken from the 

 (lardeners' Chronicle for November 2, 1912: — 



The effects produced by the exposure of seeds and plants 

 to radium emanations have been investigated by Professor 

 Molisch who finds that, generally speaking, they are disastrous. 

 Plants subjected to these emanations are in many cases 

 permanently damaged, the germination of seeds is delayed, 

 and in many cases, tor example in various leguminous seed 

 plants, such as Robin ia Pseudacacia, the leaves are thrown 

 off, even though the experiment be carried out in spring or 

 summer. If extremely small amounts of radium are used, 

 a speeding up instead of a retardation of germination may be 

 obtained, e.g., with stocks, Cucuriita Pepo [the pumpkin], 

 and Ileliunthus annniis [the sunflower]. The permanent 

 nature of the injury appears to be due to the action of the 

 emanations on the cells of the growing point, both of shoot 

 and root. A remarkable modification made its appearance 

 as a result of subjecting plants of Seditm Seiboldii to this 

 agent. Normally the shoots of this plant bear three leaves 

 in whorls, but those expo.oed to the emanations for three days 

 developed leaves arranged in opposite pairs. The mode by 

 which radium produces its effects on the cells of plants is 

 unknown, though many of its effects recall those produced by 

 poisons. It is interesting to note that the above-mentioned 

 symptoms are produced by the exposure of plants to '0000063 

 milligram of radium. 



EXPORTS FROM DOMINICA. 



The following particulars of the exports from 

 Dominica during the periods mentioned are given in 

 the Official Gazette for November 1, 1912: — 



DEPARTMENT NEWS 



Mr. H. A. Ballou, M.Sc , Entomologist on the Staff 

 of the Imperial Department of Agriculture, left 

 Barbados for Antigua bv the R.M.S. 'Tasus' on Decem- 



01 tne imperial jjepartment oi Agric 

 Barbados for Antigua by the R.M.S. 'Tagus' on Decern 

 ber 2, in order to make investigations rega 

 pests in that island 



make investigations regarding insect 



Hurricane Insurance for Coco-nut Planta- 

 tions. — Information has been received from Messrs. Henry 

 Head J^ Co., Ltd., Insurance Brokers, 27 Cornhill, E.C, 

 who have for the last few years effected insurance on both 

 the trees and crops of coco nut plantations against the risk 

 of hurricanes, in the West Indies, as to the present terms 

 and rates of premiums. These are as follows: — 



Trees: 20s. per cent, to pay the excess of 5 per cent, of 

 the value of each plantation, or 15s. per cent, to pay the 

 excess of 10 per cent, of the value of each plantation 



Crop: 30s. per cent, to pay the excess of 10 per cent, of 

 the value of each plantation. 



In the cases where the crop is insured, Underwriters 

 require the buildings of the estate to be insured as well, 

 except where they are only of trifling value. 



It may be said with reference to coco-nut insurance gene- 

 rally, that it would appear to be easier to estimate the 

 damage due to a strong wind than is the case in many other 

 kinds of cultivation. 



