232 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
and Epeira triaranea in the full sweep of a strong gale, blowing over a 
near by bay of the sea, and are scarcely damaged. Sometimes, it is true, 
the webs are blown away or lashed into threads wholly or in 
part; but frequently they will stand all the ordinary high winds 
and even some of the extraordinary ones which blow off the 
ocean. This is true even when they are spun quite near the beach, and 
have little protection under the lee of surrounding objects. 
An illustration of the remarkable strength and elasticity of the founda- 
tion lines of orbwebs appears in a biographical notice of the distinguished 
astronomer, the late Gen. 
Ormsby M. Mitchell, printed 
with an edition of 
Strength his lectures.! Prof. 
eee Mitchell directed 
Lines. his great ingenuity 
to the problem of 
causing a clock to record its 
beats telegraphically, and at 
the same time perfectly per- 
form the work of a time- 
keeper. The required makes 
and breaks in the battery 
were effected by means of a 
cross of delicate wire and a 
mercury cup. Many obstacles 
having been overcome, there 
arose the great difficulty of 
procuring a fibre 
Resists 
Wind. 
Prof. sufficiently minute 
Ormsby . Fe winietle ania 
Mitchell, 224 elastic to con- 
stitute the physical 
union between the top stem 
of the cross and the clock 
pendulum. Various materials 
were tried, among others a 
delicate human hair, the very 
finest that could be obtained, but this was too coarse and stiff. Its want 
of pliancy and elasticity gave to the minute “wire cross” an irregular 
motion, and caused it to rebound from the globule of mercury into 
which it should have plunged. “After many fruitless attempts,” says 
Prof. Mitchell, ““an appeal was made to an artisan of wonderful dexter- 
ity; the assistance of the spider was invoked; his web, perfectly elastic 
Fic. 218. Section of a dew laden orbweb. (Magnified.) 
1The Astronomy of the Bible, page 35. 
