76 



NA TURE 



[A/ay 22, 1884 



LETTERS TO THE EDITOR 



[The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers of rejected manuscripts. 

 No notice is taken of anonymous communications. 



[The Editor urgently requests correspondents to keep their Utters 

 as short as possible. The pressure on his space is so great 

 that it is impossible otherwise to insure the appearance even 

 of communications containing interesting and novel facts. ] 



Geology of the Malayan Peninsula 

 In some geological excursions made recently in the State of 

 Perak, I met with some curious facts which may be of interest 

 to many of your readers. I made boat journeys down the 

 Perak River from Enggor to the mouth, then back again 

 up the valley of the Kiuta, and then returning to the mouth 

 of the Kampar. went up that stream as far as boats can go. 

 The main chains dividing these ranges are all granitic, rising to 

 peaks generally over 3000 but sometimes over 7500 feet high. 

 The ranges are flanked by Lower Limestone ridges, forming de- 

 tached hills about 1500 feet in elevation. The summits of these 

 hills, as well as on the Hanks, are pierced with caves, which 

 contain a ferruginous clay with stream tin. The latter is evi- 

 dently derived from granite, but as the limestone hills are quite 

 isolated, and some miles away from the source of the ore, the 

 denudation of the country must have been very great. Some of 

 the caves with tin sand are 1000 feet above the plain, and have 

 to be approached by steps cut in the face of a precipice. These 

 small mines are rich enough to attract a few Malays and Chinese, 

 who are the only inhabitants. The country is otherwise a dense 

 jungle. The limestone is crystalline, without a trace of organ- 

 ism, though lines of stratification can still be traced. Tin is 

 also found in the drift at the base of these hills, entangled as it 

 is in the pinnacles and peaks of the underlying limestone. 



There is evidence of extensive denuda. on in both the granite and 

 limestone. There are no signs of any 1 cent upheaval in any of 

 this country, nor, as far as I have seen, anywhere in the Malayan 

 Peninsula, from Keddah to Johore. The country is rich in tin, 

 which has been only partially worked. 



There i andstone clay slate or gneissose forma- 



tion lying between the limestone and granite. It is much de- 

 composed, and gives rise to a red clay which goes generally by 

 the name of laterite. It is not of great thickness, but is widely 

 represented by outliers at the base of the main ranges, often 

 capping small detached hills. At the junction of this rock with 

 the granite is in my opinion the place where the great deposits 

 of tin have taken place. Wherever such outliers have been 

 denuded away the resulting drift has always been noticed by me 

 as richest in stream tin. On such drifts are the richest mines of 

 Perak, notably Larut, Kamunting, and Assam .Kumban. I 

 dont think this palaeozoic formation has been previously noticed, 

 but indeed the country is but little known geologically. The 

 slates are very like the Ordovician rocks of Australia, in which 

 so much gold has been found. J. E. TENISON-WOODS 



Thaiping, Perak, April 17 



cover any force sufficiently powerful by which this great heating 

 power may occasionally be so largely augmented as materially 

 to influence our usual winter temperatures, by bringing to our 

 shores not only a larger flow of warm water, but also impelling 

 it to strike or come into closer contact with our coasts further to 

 the south ? 



I have, in a desultory way, for a series of years noticed that as 

 a rale mild wdnters in England were associated with much ice 

 extending far south in the Atlantic. The past winter is a striking 

 example of this. Floe-ice has been more than once met with by 

 steamers in lat. 40° N. and in about the same degree of west 

 longitude, as nearly as possible midway between New York and 

 Ireland, and in the direct ship track between Jamaica and Liver- 

 pool. These conditions indicate an Arctic current of very 

 much increased volume, extending something like 400 miles 

 south and an equal or greater distance east of the position given 

 to it on any of the current charts I have examined. 



The natural effect of so large a flow of cold water from the 

 north meeting the Gulf Stream at right angles would not only be 

 to deflect the latter to the southward of its usual course, causing it 

 to si, ike our shores further south, but also in much greater 

 volume, because a larger supply is required to replace the 

 increased quantity from the Arctic 



The only specially cold winds we have had in the past winter 

 and spring have been from the east, with one or two brief ex- 

 ceptions, when there were gales from west and north-west, 

 during which the air, after leaving the Arctic current, may have 

 passed so rapidly over the Gulf Stream that it had not time to 

 acquire any great increase of heat. 



A- was to be expected from the extra quantity of ice on the 

 w , si side of the Atlantic the winter weather was unusually cold 

 and changeable in Canada and the United States, varying with 

 the direction of the winds. 



The meeting of the Arctic current and Gulf Stream has no 

 doubt been seen thousands of times. I had the good fortune to 

 witness it only once, and it reminded me — but on a far grander 

 sca i e — f two great rivers having waters of different colours, 

 joining each other at right angles, or nearly so, as I have noticed 

 with the McKenzie and some of its tributaries. 



We were coming from Portland (February i860), and our 

 excellent captain had kept far south of the usual track, to avoid 

 ice, so that for several days we were steaming in or at the edge 

 of the Gulf Stream. The meeting of the two currents with 

 their eddies— miles wide— was clearly defined, the water to the 

 north being beautifully clear and blue, whilst to the south it had a 

 brown colour with a thin film of haze over it. As we crossed the 

 eddies or "swirls" of current, temperatures were carefully 

 taken, that of the clear water being many degrees lower — I have 

 forgotten the exact difference — than the brown or Gulf Stream. 



Probably this whole question may have already been gone 

 into and fully discussed by others ; if so, the details have not 

 come under my notice. My chief object is to attract the atten- 

 tion of those who are much better qualified to deal satisfactorily 

 with this interesting subject than I can pretend to be. 



4, Addison Gardens, May 10 John Rae 



The Marine Biological Station and a Coast Survey 

 Allow me to say in reference to your article advocating a 

 Biological survey of the British coasts, that you are quite right in 

 supposing that such a survey falls within the scope of this 

 Association. As a first step in the direction of such a survey the 

 Association proposes to establish a dredging station and observa- 

 n the south coast. Later it will, it is to be hoped, be able 

 ) hlish or to cooperate in the establishment of additional 

 hedging stations on various parts of the coasts of the United 

 Kingdom, and thus gradually complete a thorough (not a super- 

 ficial) survey such as is needed. The Association will no doubt 

 k the aid of the Government when the proper time for doing 

 ives. E. Ray Lankester 



Secretary {ad interim) of the Marine 

 Biological Association 



Atlantic Ice and Mild Winters 



The influence of the Gulf Stream in ameliorating the climate 



of the United Kingdom and of the north-west corner of Europe 



71 of north latitude is 50 well known and so generally 



icknowledged that no comments are required; but can we dis- 



Right-sidedness 



In Nature for March 20 (vol. xxix. p. 477) Mr. Wharton and 

 Dr. Rae criticise my letter of the 13th on right-sidedness. In 

 writing that letter I had no intention of starting a new subject, 

 but .uily to remove one source of confusion from the subject of 

 bias in walking. But since the subject is started, I will say a 

 few words in reply. 



X either Mr. Wharton^nor Dr. Rae seem to be perfectly nor- 

 mally constituted. Dr. Rae is left-handed, indeed left-sided, by 

 inheritance (I suppose), and right-handed in some things by 

 education. In his case, therefore, the phenomena are more com- 

 1 .tit there is nothing at all inconsistent with my view or 

 at all different from what I would expect. 



Mr. Wharton is near-sighted ; his two eyes are of different 

 focal length, and his left eye is much the stronger. And yet "by 

 unconscious preference " he uses the right eye for the microscope or 

 telescope. Is it possible to have a stronger confirmation of my 

 view? 



But he says that if right-sidedness has its cause in the brain, 

 then, since I am right-handed, I ought to be left-eyed, for 

 paralysis of the right side is attended with blindness of the left 

 eye, and viceversa. Is this true in all cases ? If Mr. Wharton 

 would prove it, physiology would owe him a deep debt. We all 



