Vol. XV. No. 358. 



THE AGRICULTURAL NEWS. 



23 



BAY TREE EXPERIMENTS IN 

 MONTSERRAT. 



In his Annual Ki^poi't, Mr. IJobson, Cnrator of the 

 Botanic Station, Montserrat, f'urni.shes~the following infor- 

 mation concerning the investigations that have been carried 

 on in that island in connexion with Bay trees. It will be 

 remembered that Mr. Uinney, F.C.S., editor of the Ferfumery 

 and Essential Oil Record, has given considerable attention 

 and encouragement to the production of Bay oil in the British 

 West Indies*, so that the subject of the present article is of 

 more than usual interest. 



The experimental plot of 1 acre of Bay trees in Mont- 

 serrat is in a vigorous condition, and the yield of leaves from 

 which the oil is distilled shows a further increase over the 

 crop obtained in the previous year. It will be recalled that 

 this plot was planted in June 1908; the trees stand 9 feet 

 by 9 feet apart. The reaping of the leaves began in January 

 1911. The yield of fresh leaves and the actual amount of 

 oil obtained from tliem during the four years ending 

 December 19 -J, are as folows: — 



Actual yield of oil. 



Yield of leaves. 



1911 

 1912 

 1913 

 1914 



1,368 6,189 c.c.= 221 oz. = 14 lb. approximate. 



1,940 8,615 CO. = 307oz. = 19 „ 



2,510 12,764 c.c.= 456 oz. = 28.1 ,. 



3,256 17,687 c.c. = 631 oz. = 39 ., 



There has been a steady improveipent in the percentage 

 of oil obtained, which in 1912 was 16-7, in 1913, 18-3, and 

 in 1914, 19-5 oz. per 100 lb. of the leaves as reaped, on an 

 average of twelve monthly distillations. 



During the reaping of the leaves in 1914. more care 

 was exercised in the method of collecting for distillation, and 

 only tho.sc shoots were removed, all the leaves of which were 

 seen to be mature. This would appear to account for the 

 increase in the percentage of oil, as similar methods of 

 distillation have been adopted as in the previous year. 



The monthly distillations have been continued primarily 

 to decide if the leaves at any particular season yielded 

 a better percentage, or an oil of Ijetter quality, and the results 

 obtained in 1914, compared with similar data for the previous 

 two years, .show that no definite period of the year is indicated 

 as being desirable for the reaping of the leaves. For while the 

 reapings in the early part of 1914 are better, on the average, 

 both in yield and quantity of oil, theresults for 1912 and 1913 

 showed the best returns to be in the months of June and July; 

 nor is it shown that this is a matter that depends entirely on 

 -the distribution of the rainfall. Future work will include 

 providing a satisfactory answer to this question on somewhat 

 different lines. 



It is obvious though, from experiments, that while the 

 plants are making new growth, the reaping of leaves should 

 be avoided; and the particular periods when this was noticed 

 to develop on this plot were in April and -May, and again in 

 October and November. 



A matter of some concern is, that the quality of the oil, 

 jon the average, has declined, and taking specific gravity and 

 phenol content as the two impoitant features of Bay oil, the 

 average of the distillation for three years is: — 



Specific gravity. Phenol content. 



1912 -9484 55-5 



1913 -9460 56-2 



1914 -9342 



\f< 



505 



In the distillations hitherto, it has been the practice to 

 collect the distillate for a period of six hours only, although 

 it was known that a small amount of oil was given beyond 

 this period. To determine further the manner in which the 

 oil was precipitated, a special distillation was carried out in 

 March l9l5, when the distillation was conducted for nine 

 hours, each hour's distillate being collected, measured, and, 

 later at the Government laboratory at Antigua, submitted to 

 the usual tests; 150 lb. of fresh leaves were distilled, and each 

 hour's results, with the tests made for phenol content and 

 specific gravity are given: — 



Oil obtained in c.c 519 1st hour, 126 2nd hour, 98 

 3rd hour, 96 4th hour, 69 5th hour, 58 6th hour, 53 

 7.',th hour, 38 9th hour. Phenol content: 23 1st hour, 78 

 2nd hour, 89 3rd hour, 93 4th hour, 95 5th hour, 96 

 6th hour, 99 7.',th hour. 96 9th hour. Specific gravity ■8669, 

 1st hour, -9241', 2nd hour, 1-0259, 3rd hour, 1 0381, 4th hour, 

 1-0409, 5th hour 1-0432, 6th hour, 1-0434, 7.Uh hour, 

 1-0436, 9th hour. 



This distillation was cliieHy carried out with a view to 

 deciding if it would improve the quality of the oil to prolong 

 the distillations of the leaves to nine hours instead of six, 

 as has been practised, and the oils up to the sixth hour after 

 being l>ulked .show a (iienol content of 54 per cent, with 

 a specific gravity of -9390. Later, the oils obtained from the 

 sixth to the ninth were added, and the results then were, 

 phenol content 60 percent., and specific gravity -9472; thus 

 there is a considerable gain in quality by the addition of the 

 small amount of heavy oil from the sixth to the ninth hour, 

 and in future the distillation will be ccmtinued for a period 

 of nine hours instead of six. 



In addition to the monthly distillations in 1914, eight 

 special di.'.t illations were made to decide (1) if leaves lightly 

 packed in the still gaire better returns of oil than those 

 tightly pres.sed, (2) if sea-water used in the boiler resulted 

 in better return.s, (3) comparative results from distilling fresh 

 leaves and those dried for three days; but no C(msistent 

 results can be said to have been obtained. 



It was anticipated that from cultivated areas of Bay 

 trees, and particularly where these are grown in bush form, 

 which enables discrimination to be made in regard to the 

 maturity of the leaves collected for distillation, one of the 

 principal advantages would be the production of an oil of 

 better quality than from uncultivated trees, which is not 

 borne out as a result of this year's experiments, .so that the 

 work of the future will chiefly be concerned in deciding what 

 conditions infiuence the (piality of the oil. 



On the question of whether Bay oil deteriorates in 

 quality on keeping, tests made by Dr. Tempany show that 

 there is no change in the phenol content of the oil on a 

 sample kept for two and a half years, but that there is 

 a slight rise in the specific gravity, due, it is explained, to 

 the polymerization of the hydrocarbon myrcene which forms 

 an imporiant constituent of l>ay oil. 



*See Afjilnllutil Xeirf, V.a. XIV, No. :«0, p. .-',10. 



We notice in an Appendix to Kew Bulletin of' Miscel- 

 laneous Information containing a list of staffs in Botanical 

 iJepartmenIs at home, and in India and the co'onies, that 

 the position of Superintendent of Agriculture in IJarbados is 

 stated to be vacint. In -^pite of rumours of departure which 

 must have reached Kow, Mr. J. R. Bovell still fills the offine 

 in question. 



