November 9, 1899] 



NA TURE 



In Fig. 2 the first two families are both well seen in parts, 

 and some of the curves of the third family can be recognised. 



We may, if we choose, consider the radiating lines as the 

 perspective view of a series of parallel lines in a plane inclined 

 to X V. 



We then have the case of a row of vertical railings and their 

 shadows on the ground. 



In passing a line of such railings when the sun is low, the 

 curves, which appear to travel with the observer, may often be 

 noticed. A. Mallock. 



3 Victoria Street, S.W. , October i6. 



The Indian Forest Service. 



I AM very glad to see Prof. Schlich's defence of the Indian 

 Forest Service in Nature of November 2. I have myself been 

 very closely connected with forest administration in the Bombay 

 Presidency from 1871 to 1894. I may say that I have seen the 

 Department there grow up from little better than chaos into a 

 well-organised corps of spirited and well trained officers; and 

 there is not one word in Prof. Schlich's letter that I cannot 

 heartily support. 



Botanists can hardly be too abundant in India ; but if we want 

 good systematic botanists there, we must call them by that 

 name, and either train them specially to that science, or get 

 men so trained in the market. 



It is to me surprising that the Indian forest officers have done 

 so much botanical work as they have, to say nothing of the 

 services of several of them to zoology ; and it must be remem- 

 bered that their appointments are even now won at a consider- 

 able cost in toil and money, that their pay is not high, and that 

 their duties involve at least as much hard work of body and 



NO. 1567, VOL. 61] 



mind, as much hardship, and as much risk, as those of any 

 other service in India. 



Forestry is not all botany. It may. perhaps, be best defined 

 as the "proper management of hardy life upon large areas." 

 And the man who does that best is the best forester. We have 

 a great many who do it well, and amongst these there will 

 always be some to whom systematic botany is labour of love. 

 But to insist upon any great general proficiency in one of the 

 many subjects that a forester must study, will simply injure the 

 general efficiency of the forest corps ; and probably fail in the 

 case of the favoured subject. W. F. Sinclair. 



November 3. 



Peripatus in the Malay Peninsula. 



In a recent issue of Nature (October 19) the interesting fact 

 is mentioned of the discovery by the Skeat Expedition of several 

 specimens of Peripatus in the Malay Peninsula. Will you allow 

 me to remark that in 1886 I described in the Notes from the 

 Leyden Museum a specimen of Peripatus from East Sumatra, 

 found among a lot of insects collected by Mr. Hekmeyer, of our 

 Indian Medical Service. As it was the first specimen recorded from 

 the Oriental region, Prof. Sedgwick, in his elaborate mono- 

 graph of the genus Peripatus, considered the Sumatra species 

 to be somewhat doubtful. The specimens, however, found by 

 Mr. Evans in Kalantan appear to correspond so well with our 

 specimen, as well in the number of pairs of feet {24) as in the 

 colour, that I think a more detailed account will prove the 

 identity of the animall found on both sides of the Malaka 

 Strait. R. Horst. 



Leyden Museum of Natural History, October 30. 



A Wooden Ball of Unknown Origin. 



On the shore of the island of Haded, latitude 68" 40' about, 

 in Vesteraalin, north of Lofoten, there was found, probably in 

 the autumn of 1897, a wooden ball, 4^ centimetres in diameter, 

 covered by a thin layer of gum. The ball is of fine workman- 

 ship, and just able to float in the water. Circles are engraved 

 upon four parts, and form small rhumbs over the whole surface ; 

 and on two places there is engraved with Latin Majuscles the 

 name Melfort. Perhaps some of your readers can say from 

 whence this ball has come. I am writing to the man who has the 

 ball now, to ask him to send it to me. H. MoHN. 



Det Norske Meteorologiske Instilut, Kristiania, October 30. 



Large Nicol Prisms. 



In the account of Dr. Spottiswoode's physical apparatus, 

 lately given to the Royal Institution, there are allusions to 

 several large Nicol prisms said to have been made by Mr. Ladd 

 and by Messrs. Sisley and Spiller. Although it is no doubt the 

 trade custom to mention only the names of opticians who sell 

 pieces of apparatus, and not of any of those whom they employ 

 to make them, I still venture to hope that in this case, where 

 skill and labour of a very special kind were required, the name 

 of the actual maker of the above-mentioned prisms may not be 

 forgotten. I would therefore respectfully ask permission to 

 give a few particulars as to size, &c. , of some of the larger Nicol 

 prisms which I have myself made from blocks of Iceland spar 

 within the last thirty years. 



(1) In 1873 Dr. Spottiswoode bought a very fine block of 

 spar from Mr. Tulinius, of Copenhagen (who then owned and 

 worked the spar quarry at Eskifiordkr in Iceland). Out of this, 

 which was absolutely flawless, I made a Nicol prism having a 

 clear field of 3 J inches diameter, the length of each side being 

 12 inches. 



(2) In 1874 I made a second prism from the same block of 

 spar just mentioned, and also a third from another piece of spar 

 bought by Dr. Spottiswoode. Both of these prisms had a clear 

 field of 3i inches, the length of the sides being \i\ inches. 

 These are now at the Royal Institution. 



(3) In 1875 I made a Nicol prism for Mr. Frank Crisp, of 3^ 

 inches field and ii^ inches in length, which he used in a polar- 

 iscope in conjunction with the first one mentioned above, which 

 he had acquired from Dr. Spottiswoode. These Mr, Crisp sold, 

 and are now in England. 



(4) In 1876 I made two more large prisms for Dr. Spottis- 

 woode, one of 3-inch and the other of 2i-inch field, as spar was 



