92 



KNOWLEDGE. 



[April 1, 1895. 



attacked by the waves, and, as at Brighton, where the 

 coast-line IJas greatly receded iu historical times, costly 

 works are required to prevent further and most destructive 

 encroachments. 



THE HOUSE-SPIDER IN CAPTIVITY. 



By the Kev. Henry 1). Nicholson, M.A. 



HAVINtl caught a common house-spider, I put it 

 under a glass shade foV the night. The next morn- 

 ing it had spun some web, but all on the wooden 

 stand of the shade, with guy threads reaching 

 a short way up to its sides. Evidently the spider 

 was unable to climb up the glass, and thus was prevented 

 from making a perfect web ; so I made a sruall cage of per- 

 forated zinc, with a leiuovable glass front, to which I trans- 

 ferred the captive. The next night it made a iresh web — • 

 a tangled, shapeless festoon, sloping upwards at an angle 



1 X, v, T 



of about forty-five degrees, and secured to the roof of the 

 cage. Here the spider remained through the day, motion- 

 less in a corner on the bottom of the cage but not in the 

 web, which indeed appeared unable to support its weight, 

 except in the densest part, quite at the base. 



I then captured another spider, rather larger than the 

 first, and of a different species, and introduced it into the 

 cage. The new comer immediately prepared to attack 

 the previous occupant, marching along in a clumsy style 

 till close before its enemy. Then it reached out a long 

 leg, which action was resented by the first occupant by a 



sudden quick dart and 

 retreat, several times 

 repeated, the" intruder 

 remaining perfectly in- 

 difl'erent to the demon- 

 strations. At last the 

 first turned tail and 

 made oft', pursued by the 

 aggressor in the same 

 dogged stalking fashion 

 round and round the 

 cage. At length hostilities ceased, and I retired for the 

 night, leaving both the spiders at rest in opposite corners. 

 Next morning I found them engaged in deadly combat, 

 close locked together on the bottom of the cage. 



I immediately set the cage on a table near a window 

 with good light, arranged my camera, and took the above 

 picture. An hour afterwards the battle was over, the 

 intruder vanquished, and the conqueror was devouring its 

 victim. T'of victis ! 



Sott« Utmxt patents. 



H. F. Fostei', London. Tiu- 

 pi'ovemeuts in gas and othei' in- 

 ternal uonibnstion engines. This i.i 

 atjuulemengine. Tlie upper eylin- 

 (ter C' is the small eyltnder, and 

 the lower cylinder C' is the large 

 evliuder. t) is the trunk piston. 

 Within the trunk are two pistons 

 I I', connected together by a 

 jiiston rod K, the rod passing 

 through a stuffing box, and thus 

 forming two air cushioning 

 chambers 6 J\ lor relieving the 

 shocks arising t'roiu the explo- 

 sions. The cycle of operations 

 is as follows : — 



1. On the down stroke, the 

 top cylinder's charge is exploded 

 wliile the bottom cylinder is 

 inhaling a new charge. 



2. On the up stroke, while 

 the upper cylinder is exhausting, 

 the lower cylinder is compressing 

 its new charge. 



3. On the down stroke, the 

 lower cylinder is now exploding 

 while the upper cylinder inhales 

 its new ch.arge. 



4. On the up stroke, while the 

 lower cylinder is exhausting, the 

 upper cylinder is now compressing 

 its new charge. 



During tlie four strokes two 

 explosions are obtained. 



Xo. 20n4. Dated 31.vt J«h- 

 ,iiari/, 1894. Accepted 'i\st 



Jaiiuarij, 1895. Two figures. 



0. K. Welch, Coventry. Improvements in tension or suspension 

 wheels. This invention applies to wheels with hollow rims, havi"g 

 two thicknesses or sections of metal between the tyre and the hub ; 

 and provides a detachable cup or nipple, bearing upon both parts of 

 the tabular rim; the spoke being secured by screwing the nipple 

 upon it. The drawings consist of thirteen figures illustrating various 

 methods of carrying out the invention. 



Ho. 4419. Dated 2iid 3larch, 1894. Accepted 2nd Fehruani, 

 1895. 



C. J. Brown, London. Im- 

 provements in apparatus for 

 heating water or steam ; also appli- 

 cable for condensing purposes. 

 This invention consists of an im- 

 proved form of tube and tube plate, 

 whereby an uninterrupted course 

 is allowed for the precipitation 

 and deposit of mud, saline, lime, 

 and other impurities, and free 

 access is allowed to the exterior of 

 the tubes from both ends of the 

 heater. 



Eeferring to the figure, the in- 

 vention will be readily under- 

 stood. A is the casing, in section, 

 having the water inlet (not shown 

 in the figure) into the casing at 

 the level of c d. C is the outlet ; 

 E are the tubes ; D is an annidar 

 ttibe plate ; Gr is the steam inlet 

 and H the steam outlet The space 

 I is divided into two semi-annular 

 chambers. M is the space pro- 

 vided for the collection of sedi- 

 ment, etc- 



No. 5766. Dated 20f/i March, 

 1894. Accepted 2nd February, 1895. Four Hgures. 



