78 



NATURE 



[January 19, 1922 



Many of the bheels have been brought into cul- 

 tivation and planted with tea, and one of the greatest 

 problems in connection with the cultivation of these 

 areas has been the removal of the enormous amount 

 of water which accumulates in such places during the 

 rainy season, for, in addition to the fact that more 

 than 100 in. of rain may fall on the area in the course 

 of five months, much of the drainage-water from the 

 surrounding hillocks finds its way into the bheels. To 

 this end it has been a common practice to dig an 

 exceedingly wide and deep drain along the lowest part 

 of the bheel, which is generally near the centre, and 

 to drain into this from the edges. In this way the 

 excess water is got rid of in the rainy season, but 

 there has been an attendant disadvantage, in that 

 the bheels are often dried out completely during the 

 dry season. This occurs to such an extent that the 

 crop-yielding period is often unduly shortened, and in 

 many places it is a common practice to block up the 

 mouths of the drains at the end of the rains to pre- 

 vent excessive drying-out and prolong the period of 

 yield. 



Further, during the dry period the bushes are pruned 

 and the land hoed clean, and the area thus loses its 

 protective covering of foliage and weeds. 



In such circumstances, in which the dried-out area 

 is fully exposed to the sun's rays, spontaneous com- 

 bustion in the soil is of common occurrence, and the 

 soil becomes uncomfortably hot to walk on even in 

 heavy boots. 



Many acres of tea have been killed out in this 

 way, but no ignition of the bushes occurs above 

 ground, and it is questionable if jungle fires ever 

 originate in this way, for It Is only in the exceptional 

 circumstances outlined above that the phenomenon has 

 been found to occur. E. A. Andrews. 



Indian Tea Association, 'Tocklai Experimental 

 Station, Cinnamara, Assam, December 14. 



amount of experiment and adjustment necessary to 

 get the screens even approximately right, would be 

 quite out of reach of most workers, and could not be 

 conveniently standardised. Further troubles enter 

 with small alterations in the light source due to age 

 and variation of voltage, the general Illumination of 

 the laboratory, and, not least, the personal equation. 



H. J, Denham. 

 Shirley Institute, Didsbury, January 4. 



Microscope Illumination and Fatigue. 



Mr. Barnard's letter In Nature of December 29 

 last, p. 566, Is unusually dogmatic as a contribution 

 to a scientific discussion. As the title of this corre- 

 spondence indicates, the original letter was written, 

 not so much to direct attention to a particular method 

 as to a general principle, with the intention of 

 Increasing the comfort of workers who have to work 

 long hours at the microscope. It appears that Mr. 

 Barnard has arrived at the same principle Indepen- 

 dently, but in a case of this nature there is no excuse 

 for withholding from publication a matter which 

 affects the well-being of a large number of workers. 



Mr. Barnard condemns the method employed, but 

 perhaps without having given the system described 

 an unprejudiced trial. The ultimate test of any 

 method lies in actual practice. Before publication the 

 resistance-controlled illumination was tested out com- 

 pletely within the limits stated. Imposed by the use of 

 light-filters and the nature of the work of this labora- 

 tory. Since Mr. Barnard brought up the question 

 of the shift of the dominant radiation— which was 

 irrelevant at the time — further tests have been made 

 with the unscreened light (which is never used for 

 critical work here), and it was found that there was 

 no perceptible loss of resolution or colour differentiation 

 with the lowering of the current. The shift of the 

 dominant is thus not a cause for alarm. A further 

 test showed that to produce equivalent results with 

 neutral filters some eight or ten screens would have 

 to be made, and even then the optimum for every 

 small variation of staining or thickness of section 

 could not be obtained. Such an outfit, with the large 

 NO. 2725, VOL. 109] 



Tin Plague and Arctic Relics. 



Referring to the letter on tin plague in Nature of 

 December 15 last, it may be of Interest to record that 

 in the Museum of Fisheries and Shipping at Hull, 

 among a number of Arctic and Antarctic relics, we 

 have two tins, each about 6 in. in diameter, provided 

 with a thin Iron handle on the top soldered on to 

 assist in carrying. These tins, according to the 

 " Guide to the Museum of the Hull Literary and 

 Philosophical .Society," published In i860, and con- 

 firmed by that society's minutes, were picked up, 

 among other relics and stores left by Capt. Parry, on 

 Fury Beach In 1825. They were found by Capt. 

 (afterwards Sir John) Ross in 1831, who brought them 

 away with him. Capt. Ross was picked up at sea 

 In a boat by Capt. Humphreys, of the Isabella, 

 a whaler of Hull, in 1833, and these relics, among 

 others, were In the boat with him. They were brought 

 to Hull and given to the Literary and Philosophical 

 Society. Eventually this society's collection was 

 handed to the Hull Corporation. 



About ten years ago I was curious to know the 

 contents of these two tins, and had them opened ; 

 one was found to be full of corned beef in excellent 

 colour and condition, and the other contained pea- 

 soup. Both seemed to be quite fresh, and my 

 attendant sampled them and stated that they were 

 quite good and sweet. He still lives. The soup and 

 the meat are now exhibited in glass jars, and are still 

 In good condition. 



My object in mentioning these facts is to show 



that after being left in the Arctic between 1825-31, 



and then taken charge of for another two years by 



Capt. Ross, which means that they were more or 



less subject to Arctic conditions for eight years, and 



then having been in Hull for eighty years, the metal 



does not seem to have deteriorated in any way and 



I it had had no effect upon the contents. Possibly this 



j may be due to the fact that the tins were painted 



with a thick coat of yellow and green paint respec- 



I tlvely, which may have prevented any "plague." If 



this is the cause, the circumstances may be of value 



on future expeditions of this character. 



The Museum, Hull. T. Sheppard. 



Inheritance of a Cheek-Mole. 



Perhaps the following case of the Inheritance of a 

 mole on the cheek for three generations may be 

 Interesting. Records do not go back any further, 

 but, as the representative .of- the present generation 

 is nineteen, it may be possible to see whether it is 

 continued. The grandfather had a peculiar mole right 

 in the middle of his left cheek. Of his children, two 

 daughters both showed It in almost the same 

 position. The sons did not, but one daughter of one 

 son now has it. There are two boys and two girls- 

 in familv, but it has appeared only on one girl. 



G. W. Harris. 



The Royal Automobile Club, London, S.W. i, 

 December 25. 



