254 



HARDWICKE'S SCIENCE-GOSSIP. 



I placed one of these young spiders in a suitable 

 place, and it immediately began to construct a web, 

 completing it in thirty minutes. These webs are 

 very small at first, only some two or three inches 

 in diameter, and the small creature is content to 

 sit in the centre for a week or two, probably that 

 it may the more readily catch the luckless midges 

 that fly into the web ; but in a few weeks, possibly 

 through some law of development, it connects this 

 centre by a cable to some convenient corner, where 

 it has constructed its parlour. 



I have succeeded in taking some facsimiles of 

 these young spiders' webs, which are sent here- 

 with ; and though not as perfect as could be wished, 

 they may interest your readers, if they can be re- 

 produced by the wood-engraver (see figs. 152 to 155). 

 The one marked 152 is a copy of the web just 

 referred to, made by a spider just out of the cocoon 

 in thirty minutes; but unfortunately there was a 

 failure in the copying, which I much regret, as the 

 web itself was the most perfect one I ever had 

 under the copying process. In constructing the 

 circular portion of this web, the spider began in 

 the centre and laid down the spiral by circuits, 

 constantly increasing in diameter till it reached the 

 extremity, when, reversing the order of its course, 

 and going from left to right instead of from right 

 to left, it laid down intermediate lines between 

 those already made, till it got back to the centre 

 agaiu. 



Thinking it may be useful to spider-students, I 

 shall now explain the system by which I have taken 

 copies of these fragile structures, — a system which 

 may, if others try it also, be brought to greater 

 perfection in another season. Observing one day 

 in April last a window-pane covered with small 

 spiders just out of the cocoon, and being unable to 

 see any webs, even with an ordinary pocket lens, 

 they were so fine and free from dust, the thought 

 occurred to me that if the webs could be dyed some 

 colour, it would render them visible, and then the 

 exact form of the circles could be seen. Others, 

 examining them at the same time, thought that 

 there were no webs, but that the spiders were all 

 suspended by their threads. Breathing upon them, 

 however, produced a vibration in the spiders, and 

 this convinced me that each was' occupying the 

 centre of an elastic and invisible web, and I at once 

 began to try if they could not be dyed. 



To accomplish this, 1 employed one of Mr. 

 Siegle's Patent Steam Spray Inhalers, — an appara- 

 tus that is used for injecting remedial agents into 

 the mouth for sore throat, &c. Into the small 

 phial connected with this apparatus some aniline 

 blue was introduced, the steam raised by a spirit- 

 lamp, and, after the spider had been compelled by 

 a few puffs of tobacco-smoke to vacate its position, 

 the blue spray was showered all over the web, 

 making it distinctly visible to the naked eye. 



After getting thus far, it occurred to me that by 

 bringing sheets of white paper gently into contact 

 with these dyed webs while they were still wet a 

 facsimile might be obtained ; and on putting this 

 thought into action I obtained the accompanying 

 results. 



If these results are put under a good magnifier, 

 it will be seen that small globules stud the radii as 

 well as the circular part of the web, and my first 

 impression on observing this was that the generally- 

 received opinion that the viscid adhesive liquid 

 which coats a spider's web is found upon the spiral 

 part only was incorrect. But in considering fur- 

 ther, and recollecting that the vehicle for conveying 

 the colouring matter was steam, it occurred to me 

 that this, by throwing the colour upon the web in 

 globules, may be the cause of the dots upon the 

 radii. As there is, however, some uncertainty on 

 this point, the subject may well deserve further 

 investigation. 



By making a specially-arranged framework, upon 

 which the young spiders could spin their webs, 

 more accurate results might be expected ; and 

 perhaps some of your readers may, through the 

 foregoing hints, be induced to experimentalize in a 

 direction which I hope to pursue myself in the 

 spring of next year. C. L. W. 



DAMAH, AS A MOUNTING MEDIUM. 



I THIN K there are many amateur mounters who 

 would use Damar in place of Canada balsam 

 did they only know that it can be procured done up 

 in tubes, so that the mounter has only to apply a 

 slight pressure to the tube, and the damar flows 

 freely on to the object. I am not aware that any 

 notice of these tubes has been given in Science - 

 Gossip, at least no such notice has appeared since I 

 first became a subscriber, in 1872, to this popular 

 journal. I believe that Walter White, of Litcham, 

 Norfolk, is the only preparer of damar in the way 

 I have above mentioned. Bound every tube 

 (which I may here mention costs Is.) is wrapt a 

 paper containing a few remarks on damar. From 

 these I take the following : " Very fragile objects 

 may be successfully mounted in damar with the 

 greatest ease by merely laying the object on the 

 slide, covering it with a thin glass cover, and allow- 

 ing the medium to run under by capillary attrac- 

 tion. If a very slight pressure be applied to the 

 cover, and the slide put away iu a warm place, it 

 will be ready for finishing in a day or two. In 

 finishing a slide it is necessary, after the superfluous 

 damar has been removed and the slide properly 

 cleaned, to lay on [the edge of the cover a coat of 

 some tough varnish, to prevent the cover from 

 being accidentally moved in hot weather. A solu- 

 tion of shellac in spirit is a good varnish for the 



