Yc 



Sir, 



Properties af the Weh »/ the Garden-Spider. 369 



XII, 



On the Weh of the Garden-Spider. By a Correfpondent. 

 To Mr. Nicholson. 



OU have, probably, often remarked the peculiar conftrudlion of the web of what, I 

 think, is called the garden-fpider. This web is compofed of threads radiating from a cen. 

 tre, and nearly equidiftant ; thefc are interfe6led by others, which bear fome refemblance to 

 concentric circles. I remarked, feveral years fince, a very ftriking difference between the 

 circular and radiating thread ; if the former be touched with the finger, they will adhere to 

 it fo tenacioufly, as fometimes to break upon withdrawing it, although their elafticity is fuch 

 that they may be extended to more than double their ufual length ; which, however, they 

 inftantly refume, upon quitting the body to which they adhered. On the contrary, the ra- 

 diating threads appear totally deftitute of the adhefive property, and never indicated the leaft 

 difpoficion to attach ihemfelvts to any fubftance I prefented to them. Having remarked that 

 the infeiSt often doubles, and fometrimes triples the radiating threads ; that thofe which ferve 

 as boundaries to the web, to which the extremities of the former are fattened, are frequently 

 compofed of feven or eight fingle threads united by the fpider, fo as to form but one which, 

 as well as the former, is not poffeffed of the adhefive property) ; and that thofe of the circular 

 kind are always fingle ; I was at firft induced to attribute the abfence of the adhefive property 

 in the two former to their exerting this property upon each other. To fee how far this idea 

 would agree with fa£ts, I united feveral of the circular threads; but upon trial, no diminu- 

 tion of their tendency to adhefion was perceptible. In the almoft innumerable experiments 

 I have made fince this phenomenon (if it can be termed fo) was firlt obferved, the refults 

 have been uniformly the fame, not only when the finger has been employed, but with every 

 fubftance with which the experiment has been tried. 



It appears that this remarkable difference is not occafioned, nor in any perceptible degree 

 influenced, by the ftate of the atmofphere, nor by the fize, nor confequently by the age of the 



fpiders*. ' - 



I am. Sir, with great refpeft, 



• Your humble fervant, 



J.L. 



* This faft is fomewhere mentioned, but I cannot recolleft the place. It is affirmed that the fpider 

 walks only on the radial threads. 



In anfwer to the queftion in the poftfcript, requefting me to indicate an elementary chemical work con- 

 taining dirc£tions for condu6ting the various chemical proceCTes, defccipiions of apparatus, and a full expla- 

 nation of the new chemical nomenclature, I mull obferve, that we have no modern book which defcribes the 

 procefles with the minutenefs and fidelity of Boerhaave, or Shaw, in their leftures ; but that the elements of 

 Chaptal, and of Lavoifier, are found difcurfive treatifes, written according to the modern fyllem. Tables of 

 the chemical nomenclature have been publiihed in Eiigliih, by Dr. Pearfon and otbers.^N. 



Pla 



