42 



NATURE 



[May 17, 1877 



Patenas in Ceylon 



I REGRET that through an .iccidcnt I was able only yesterday 

 to read Mr. Heelis's reply to my letter on the subject of jiatenas 

 in Ceylon. I have not a copy of my own letter by me and 

 therefore cannot speak with certainty, but I believe that I only 

 suggested that the cropping out of the thick band of quartzite 

 amongst the gneiss was sufficient to explain the existence of 

 many of the larger patenas in the Kandyan Trovince. Tlie im- 

 mense majority of the smaller and more isolated patenas I am 

 fully aware cannnot be explained on my supposition, nor can they 

 at present be explained on any reasonable supposition. I do not 

 think, however, that even the most superficial observer can have 

 any doubt as to the large patena mentioned in my letter between 

 Pussellawa and Rambodde, covering several thousands of acres, 

 being entirely due to the quartzite band that lies above it. In 

 regard to the Dimbula patenas it is no doubt true that gneiss is 

 almost always found underlying the soil, but this does not prove 

 that the patena soil is derived from the gneiss. The depth of 

 the rock below the surface is against this view, especially when 

 taken in connection with the fact that I was never able to trace 

 in the case of patenas as I did in scores of cases of jungle land, 

 in railway and road cuttings throughout the Kandyan Province, 

 the gradual changes from the hard rock upwards to the surface, 

 which show that the soil has been produced by the disintegration 

 of the gneiss in situ. The denuding forces at work among these 

 mountains are so excessive (according to an estimate made by 

 myself at Pussellawa the denudation was no less than ten inches 

 in thirty years on land cleared for coffee) that strata probably 

 of many tliousands of feet in thickness have been carried away 

 to the low country and the sea. It is not, it seems to me, at all 

 an improbable supposition that in Dimbula and Ouvah a band 

 of quartzite has during this denudation been disintegrated, and 

 that its remnants are found now in isolated places restnig on the 

 gneiss. The limestone mentioned by Mr. Heelis as occurring 

 in the Ouvah patena district proves, I think, a point in my 

 favour, for the same kind of limestone is more plentiful in the 

 neighbourhood of the quartzite band between Pussellawa and 

 Rambodde than in any other district with which I am acquainted, 

 there being no less than five entirely isolated spots near these 

 villages where it occurs. This limestone is highly crystalline and 

 of the same age as the gneiss, for I have found it at the upper 

 fall at Rambodde passing almost imperceptibly both above and 

 below into the gneiss. It is here about 450 feet above the upper 

 surface of the quartzite band, where it crops out in the lower fall. 

 Its stratified character may be readily seen at Pussellawa by the 

 bands of mica-fragments that run through it in almost hori- 

 zontal directions. I have never heard of this limestone cover- 

 ing any extensive area except at Matale, where there must 

 be some hundreds of acres of it. In other localities that 

 I have visited it covers only an acre or more frequently 

 only a fraction of an acre. The soil produced by its disin- 

 tegration is, 1 believe, the richest in the island, as is shown 

 by the fact that the limestone after being burnt is frequently used 

 as a manure for coffee trees, and that the jungle growing below 

 such rocks is generally of the richest description. I can scarcely 

 therefore think that any considerable area of patena soil in Ouvah 

 is formed by the disintegration of limestone, although it is quite 

 consistent with what occurs at Rambodde that limestone should 

 be extensively found in the neighbourhood of a large patena. 

 As to the quality of the soil on the Ouvah patenas the test 

 generally applied by planters is that of the power of the coffee 

 tree to produce fruit. This is manifestly not a perfect test. 

 Climate counts for a great deal, and the climate of Ouvah is 

 recognised as the most favourable in Ceylon for the production 

 of coffee, whilst that of Dimbula is acknowdedged to be too 

 humid for the peifect fruiting of the plant. I remember a per- 

 tinent remark made to me by a successful planter in regard to 

 the relative values of soil and climate in the growing uf coffee. 

 "Give me the climate and I can make the soil." It is an 

 exaggeration, but there is suflicient truth in it to illustrate well 

 the point I am urging. 



Finally in regard to abandoned clearings falling back not into 

 "chena"and jungle but into patena land, I must confess I 

 never met with an instance of it, and with Mr. Ileelis' permission 

 I would suggest that the Dimbula cricket ground is scarcely a 

 case in point. It is probably the interest of the owner to keep 

 it in grass and to prevent seeds accidentally carried to it from 

 taking root. But [supposing it were surrounded by forest and 

 left to itself for twenty years, would it at the end of that period 



be still in grass, or would it have returned to "chena"? If it 

 were ge nuine patena land, it would remain so, for plants acci- 

 dentally imported into it would find no nourishment, but if it 

 were impoverished jungle soil, I am inclined to the opinion that 

 there would still be sufficient unextracted nourishment to enable 

 at least the hardier species to grow in a stunted form until humus 

 was deposited, when forest would succeed. Whilst differing 

 from Mr. Heelis on the several points of his letter I cannot omit 

 to thank him for the courtesy with which he has expressed his 

 opinions. R. AuisAY 



Ouseburn, May 10 



The Greenland Seal Fishery 



Another year has passed and no steps have been taken to 

 put some restriction upon thecruel.and wasteful manner in which 

 the seal fishery is prosecuted. V/arning after warning has been 

 given, and still nothing has been done. In 186S Dr. Brown 

 wrote (Pivc. Zool. Soc, p. 440) : " Supposing the sealing prose- 

 cuted with the same vigour as at present, I have little hesita- 

 tion in stating my opinion that, before thirty years shall have 

 passed away the seal-fishery, as a source of commercial revenue, 

 will have come to a close." This season the Dundee vessels 

 have been turning their attention to the Newfoundland seals, for, 

 says a paragraph in the Daily Nl-l<s, " Capt. Adams has for some 

 years been of opinion that that ground [the; Greenland seal- 

 fishery] is practically used up, and hence his visit to Newfound- 

 land." The small success of the Greenland sealers this season 

 fully corroborates Capt. Adams's opinion, aud forms a practical 

 comment upon Dr. Brown's prediction ! 



From the same source {Daily News) I learn that " advices of 

 a very gratifying character have been received from Newfound- 

 land. The Paiillur has taken 20,000 seals, the Neptune 30,000, 

 the Arctic 24,000, the Autora 15,000, and high expectations 

 have been formed regarding the success of the whole fleet. These 

 four vessels have secured 89,000 seals ; Capt. Gray says 20 per 

 cent, may be added to the number of seals actually taken for 

 those mortally wounded and lost, aud that as these are breeding 

 seals each old one will leave a young one to die of starvation. 

 (See letter in Land and Water, May 9, 1S74.) The result will be 

 that these four vessels destroyed 213,000 seals ! Similarly 

 "gratifying" advices have been received from the other vessels 

 of the fleet. 



If the Royal Society for Prevention of Cruelty to Animals 

 and the anti-vivisection advocates really wish to do "service 

 in the cause of humanity, let them reprint Capt. Gray's 

 letter and distribute it broadcast, nor let tViem cease their 

 efforts till a projier close time is obtained for these persecuted 

 animals. Apart from all questions of humanity, common 

 prudence would dictate that so rich a source of revenue, which, 

 if properly cared for, may last an indefinite period, should 

 be secured from the rapacity of those who will otherwise soon 

 bring about its extinction. Now is the time for considering the 

 steps which should be taken to bring the matter before the 

 Governments concerned ; if left till later in the year hasty legis- 

 lation will probably, as in the last attempt, end in failure. 



Norwich Thomas Sovnivif ell 



A New Lecture Experiment for Proving the Compound 

 Nature of White Light 



The old method of showing the compound natui'e of light by 

 the composition of artificial colours on the lecture-table, is to 

 arrange the various colours in the proper proportioi on a disc 

 and to revolve this disc rapidly ; but a pure while ciitiot be pro- 

 duced by this method since there is necessarily a pa'tial absorp- 

 tion of rays on every part of the disc. 



My method is to arrange seven lanterns, in tht first place, 

 so as to project their several circles of light side by side on a 

 white screen, then to colour each circle by introdu:ing slides of 

 glass stained to imitate the seven colours of the spectrum (the 

 proper intensity of colour being found by trial) we thus get 

 seven circles on the screen coloured from red :o violet and 

 arranged side by side. Then by turning the sevenl lanterns so 

 that the projected circles shall exactly overlap eacholher we get 

 one circle of white light, proving that the seven coburs together 

 make white light. 



The same effect can be produced with five colours oily if pro- 

 perly selected ; and even two, the ordinary cobalt blu( and deep 



