340 



NATURE 



[June 22, 1916 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other part of Nature. No notice is 

 taken of anonymous communications.] 



Elasticity and Entomology. 



While Euler's problem of the buckling of elastic 

 rods and shafts under end thrust has received much 

 attention both from mathematicians and from 

 engineers, the importance of the results does not 

 appear to have been appreciated in the entomological 

 world. 



I have been recently attempting to rearrange an 

 old butterfly collection mounted in the so-called "Con- 

 tinental " fashion, high up on entomological pins 

 about 1.5 in. long, and I find that except in the case 

 of the thickest pins elastic instability invariably 

 occurs when it is attempted to insert the specimens 

 in the cabinet. This effect causes great trouble and 

 inconvenience even with pins of thickness suitable for 

 mounting average-sized Lyceaenidae. The drawers of 

 my cabinet are lined with peat, coated with a thin 

 layer of cork, and are specially constructed for the 

 purpose, so the resistance is not great. 



In the case of brass pins "made in Germany " it 

 is impossible to insert them from above without per- 

 manently bending, and often doubling them up. In 

 this case the flexure due to buckling causes permanent 

 "set." Steel pins, on the other hand, are not usually 

 bent beyond the elastic lirnits, but the result of the 

 buckling is to cause the end of the pin to take a 

 wrong direction when it is driven into the box; con- 

 sequently, when the forceps is removed, the insect 

 springs back into a position different from that 

 originally intended, not only causing the collection 

 to look very unsightly, but often resulting in the 

 antennae breaking off in consequence of the momen- 

 tum generated in them by the vibration. The effect 

 of excessive strain in the case of steel would probably 

 be to break the pin in two. 



It is curious that when studying these problems 

 in elasticity nearly thirty years ago the idea never 

 occurred to me to apply the results to account for 

 the incessant troubles and misfortunes which in later 

 years resulted in my abandoning entomology as a 

 hobby. The present experiences, affording as they do 

 a theoretical explanation of the difflculties, prove con- 

 clusively that the Continental system of setting butter- 

 flies and other insects high up on long German pins 

 is fundamentally wrong In principle, and entomolo- 

 gists would do well to take account of the phenomena 

 of elastic instatwlity in deciding the style in which 

 they mount their future collections. 



It would be the easiest thing In the world to cal- 

 culate the maximum length of pin of a ^iven thick- 

 ness that could be driven without buckling Into a 

 cabinet drawer or store-box offering a given resist- 

 ance, but the question Is so easllv decided by trial 

 that a mathematical investigation appears scarcely 

 necessarv, G. H. Bryan. 



Babylon's Sacred Way. 



The discovery of the Sacred Way, or Procession 

 Street, of Babylon is one of the results of excavations 

 carried out by Dr. Robert Koldewey on the site of 

 this ancient city. This Sacred Street extended ap- 

 proximately north and south through Babylon so far 



NO. 2434, VOL. 97] 



as the south-east corner of a level quadrangular en- 

 closure wherein was situated the famous 'lower of 

 Babylon. Here the Sacred Way turned sharply west- 

 ward towards the Euphrates, where the stone piers 

 of the bridge which spanned the river have been found. 

 All the temples of Babylon, including those of the 

 goddess Ishlar and of Marduk, the lord of Babylon, 

 have been found in the vicinity of this Sacred Way 

 on either side. The street was extended slightly west 

 of north and east of south, and the temples were 

 similarly oriented, the southward aspect being approxi- 

 mately S.S.E. Apparently no attempt has been made 

 to ascertain the azimuth of any of the temples, or of 

 the Procession Street. Prof. Leonard W. King, in 

 his recently published " History of Babylon," states 

 that ■■ Nebuchadnezzar boasts that he paved the street 

 of Babylon for the procession of the great lord Mar- 

 duk, to whom he prays for eternal life " (p. 59). 



The foundation of the Sacred Way was laid with 

 burnt bricks. The pavement throughout its entire 

 length was constructed of square slabs, those in the 

 middle being " a fine hard limestone," those along 

 each side being of "red breccia veined with white"; 

 but along that part of the Sacred Way between the 

 royal palace and the main entrance to the enclosure 

 of the Tower of Babylon the pavement was formed 

 entirely with slabs of breccia. A plate facing p. 60 of 

 the " History," showing part of the Procession Street 

 uncovered, makes It appear that the slabs were about 

 18 in. square. They were held firmly in position by 

 being laid on bitumen, which also filled the inter- 

 stices between the slabs. 



Dr. R. Koldewey thinks the limestone may have 

 been obtained from Hit, on the Euphrates. Prof. 

 L. W. King has Informed me, in reply to an inquiry, 

 that "it is not yet known whence the breccia for the 

 Sacred Way was obtained, though at the time of Its 

 discovery Dr. Koldewey consulted more than one 

 geologist on the subject." 



Inscriptions on the edges of the slabs record that 

 the pavement was constructed bj^ Nebuchadnezzar 

 (604-561 B.C.); but It is recorded on many of the 

 slabs of breccia that they had formed part of an earlier 

 pavement which had been the work of the great 

 Sennacherib (688-681 B.C.) during the Assyrian 

 domination. It would be Interesting to know from 

 what quarries the breccia and the limestone were 

 obtained. 



Bv his extremely valuable " History of Babylon," 

 Prof. L. W. King has placed archaeolog'Ists and all 

 interested in ancient civilisations under a heavy debt of 

 obligation. The long chapter dealing- with the most 

 recent discoveries, with numerous plans and illustra- 

 tions, is a treatise in itself of thrilling interest. 



H. KiDNER. 



194 Shelbourne Road, Bournemouth. 



P.S. — Since the foregoing letter was in type I have 

 made a closer examination of the plans of the city 

 and of its temples, published in Dr. King's " History 

 of Babylon." 



The plans on pp. 74 and 83 show that the part of 

 the Sacred Way leading J;o the Euphrates branched 

 from the main street at an angle of about 87°. This 

 part of the street was oriented about 10° to 12° N. of 

 E. and S. of W. The street passed alongside the 

 eastern and southern wall of the peribolos of the 

 Temple Tower, and in this latter part of its course 

 towards the river It had the tower on the right (N.) 

 and the Temple of Marduk on the left (S.). Prof. 

 King states that the main street doubtless also con- 

 tinued southwards to a gate In the southern wall of the 

 citv. 



