204 



NATURE 



Sjfan. 1 1, 1872 



Pupa of Papilio Machaon 



Whilst working at the colour patterns of Insects in Novem- 

 ber 1867, I very carefully dissected off a portion, about one- 

 eighth of an inch square, of the hard integument from the side 

 of°a pupa of P. Machaon, near the anterior extremity. The por- 

 tion of the interior thus displayed was filled with a clear colour- 

 less fluid, in which was floating a delicate membrane, to which 

 were a'tached several tubes, trachea, formed by a spiral fibre. In 

 the fluid were floating many roundish grains. Another pupa of 

 the same brood was examined January 15, 1S68, and another on 

 April 15. The floating grains were now evidently made up of 

 t^anglia of the spiral fibre of the trachea, and were connected with 

 the tube by long pedicels of the same kind of fibre. On May 20 

 the tubes had enlarged to such an extent that they were almost 

 contiguous, and were covered with minute granules, apparently 

 incipient scales ; in fact, a few small but well-formed scales 

 appeared on one portion. The specimen examined in November 

 was laid in cotton ; a perfect cicatrice was formed, and the butter- 

 fly in excellent condition appeared at the usual time. 



Rainhill, December 23, 1871 Henry H. Higgins 



Lunar Calendars 

 In reply to "Myops" inNATURE, No. iii, p. 123, the English 

 New Moon of the Jews is really the Momh-Head (Caput mensis), 

 formed from an artificial system. The true mean conjunction 

 derived from the 19-year cycle is called the Molad or Moon- 

 Birth, and generally differs from the festival-day. 



Said artificial system consists in combining AZ, BY, CX, &c., 

 as follows : — 



ist Day of Pas;over has Black Fast (glh Ab) on same week day. 

 2nd ., 1st of Pentecost. do. 



3rd „ „ „ istof New Year(Tishri). do. 



4lh „ „ ,, L.ist of Tabernacles— Rejoicing of Law. do. 



5th „ „ ,, White Fast (Atonement Day). do. 



6[b ,, ,, ,, Preceding Purim (Esther's Feast, do. 



This actual Jewish Calendar depends on the ISIoveable Feasts, 



1st Passover never falling on Monday, Wednesday, or Friday.* 



39, Rowland Street, W., Dec. 15, 1871 S. M. Drach 



Hints to Dredgers 

 Appealed to by name — spirits from the vasty deep — I have 

 waited for my elders, also named, to answer Mr. Ilennah's 

 queries .about dredging, and, failing to see anything more, I 

 venture to trouble you with a few lines, the more so as I felt the 

 want of advice when I was fitting out the A'orna in 1870. 

 Details would be out of place here ; I will only at present give a 

 few liints. And first — to repeat Puncli's advice to those about to 

 jnarry— if about to buy a yacht. Don't ! Begin by hiring one of 

 the tonnage you require, tlie proper price being i/. 5,1. per ton 

 per month, including the wages of skipper and crew, but rarely 

 of cook or steward. After your first season buy by all means if 

 you like. 



If bound on a long cruise your craft should not be under 80 to 

 100 tons. Bat for dredging in the Channel or round our coasts 

 25 tons and upwards are sufficient ; but not on any account under 

 that. A little boat of 25 tons makes up two good berths and 

 two more possible ones, exclusive of the crew's sleeping quarters, 

 and being decked stands a good chance in a gale of wind. 



Beware the discomfort of a half-deck and a small boat, remem- 

 bering that you may unavoidably have to face some nasty breezes 

 which an ordinary yachtsman would run away from. You may, 

 for instance, be caught in a bay offering rich results, and have to 

 thrash cut of it. 



Hire a man knowing the locality in which you desire to try 

 your fortune. 



Take a particular line, say the comparative life on the borders 

 of fresh and salt water junctions, or at spots where tlie depth 

 suddenly increases. No better locality, with a good pilot, could 

 be picked out to begin with than the Channel Islands. 



Especially note the submarine geology. Exactly fix the spots 

 you dredge in by cross bearings. A small prismatic compass is 

 invaluable, both afloat and ashore. Take careluUy temperature, 

 current, tidal observations, a multitude of soundings, and keep 

 specimens of all. Fill a private log-l)Ook with the most trivial 

 and infantile details. You will afterwards laugh at much you 

 have noted ; but it is a great gain, and, unlike partridges, im- 

 pressions are best fresh. 



» For Mahommedan Calendar inquire of a Moslem, or such an authority 

 as'Capt. R. J. Burton, the famous Hajji El-Iraki, and Consul to E1-3'/mot. 



This is not the occasion to go into matters of outfit. One 

 thing I must name, on no account let any man on board be with- 

 out a life-belt for his own use. 



Any intending dredger writing to me at this club will be 

 cordially answered. A small squadron of yachts working 

 together under a commodore of their own election would parti- 

 tion the labour, and produce a little emulation among the crews. 

 Make a rendezvous every few days, and talk results over. 



Marshall Hall 



New University Club, St. James's Street, S.W., Jan. 6 



Anacharis Canadensis (A. Alsinastrum) 

 I SHOULD esteem it as a favour if you would allow me to 

 ask, through the meHium of Nature, if there be any published 

 account of observations, confirmatory or otherwise, of Mr. 

 Wenham's notes on the free-cell formation which he has described 

 as being carried on at the terminal growing point of Anacharis, 

 quoted by Dr. Carpenter in " The Microscope and its Revela- 

 tions," p. 405, et SCI/. (3rd ed.) H. Pocklington 



FIGHT BETWEEN A COBRA AND A 

 MONGOOSE * 



THE snake was a large cobra 4ft. 10^ in. in length, the 

 most formidable cobra I have seen. He was turned 

 into an encloeed outer room, or verandah, about 20ft. by 

 12 ft., and at once coiled himself up, with head erect, about 

 ten or twelve inches from the ground, and began to hiss 

 loudly. The mongoose was a small one of its kind, very 

 tame and quiet, but exceedingly active. 



When the mongoose was put into the rectangle, it 

 seemed scarcely to notice the cobra ; but the latter, on 

 the contrary, appeared at once to recognise its enemy. It 

 became excited, and no longer seemed to pay any atten- 

 tion to the bystanders, but kept constantly looking at the 

 mongoose. The mongoose began to go round and round 

 the enclosure, occasionally venturing up to the cobra, ap- 

 parently quite unconcerned. 



Some eggs being laid on the ground, it rolled them near 

 the cobra, and began to suck them. Occasionally it left 

 the eggs, and went up to the cobra, within an inch of its 

 neck, as the latter reared up ; but when the cobra struck 

 out, the mongoose was away with extraordinary activity. 



At length the mongoose began to bite the cobra's tail, 

 and it looked as if the fight would commence in earnest. 

 Neither, however, seemed anxious for close quarters, so 

 the enclosure was narrowed. 



The mongoose then began to give the cobra some very 

 severe bites ; but the cobra after some fencing forced the 

 mongoose into a corner, ard struck it with full strength 

 on the upper part of the hind leg. We were sorry for the 

 mongoose, as but for the enclosure it would have escaped. 

 It was clear that on open ground the cobra could not have 

 bitten it at all ; wliile it was the policy of the mongoose 

 to exhaust the cobra before making a close attack. The 

 bite of the cobra evidently caused the mongoose great 

 pain, for it repeatedly stretched out its leg, and shook it, 

 as if painful, for some minutes. The cobra seemed ex- 

 hausted by its efforts, and putting down its head, tried 

 hard to escape, and kept itself in a corner. The mongoose 

 then went up to it and drew it out, by snapping at its tail, 

 and when it was out, began to bite its body, while the 

 cobra kept turning round and round, striking desperately 

 at the mongoose, but in vain. 



When this had continued for some time, the mongoose 

 came at length right in front of the cobra, and after some 

 dodging and fencing, when the cobra was in the act of 

 striking, or rather, ready to strike out, the mongoose, to 

 the surprise of all, made a sudden spring at the cobra, and 

 bit it in the inside of the upper jaw, about the fang, atd 

 instantly jumped back again. Blood flowed in large 

 drops from the mouth of the cobra, and it seemed much 



* The following interesting narrative has been obligingly forwarded to lis 

 by Prof. Andrews, of Queen's College, Belfast. 



