554 



ANCIKNT DKSKMEKS OK STKKLYAKDS. 



woiiilit must Im' coii'cct. This riu^^^ ])n'vcn(('(l citlicr |):ui from s'mkiiijr 

 too far. 



N(Mth('r of these iirranj^omeiits allowed the l>eam more than a \ cry 

 limit(Ml i^lay, and from this it may be inferred that they lacked one of 

 the primt' reijuisites of a f^ood l)alanee. namely, that tln^ e(|uilil»rium 

 should he stable, ho that when unloaded oi- carryino- eijual load.s the 

 l)eam should tend to return to the horizontal position, howt'ver far it 

 mi^lit ha\-e been displaced. A later improvement was to suspend the 

 l)eam t)y a rin*;- attached to its upper side in the middle, as is seen in 

 fiL'". 7. from Ko;ypt and H<r- '••• from Ja])an. The same mode of sus- 

 pension was employed in the (•orrespondinj:^ stiige of development of 



the balance in ancient 

 (Ireece and Home. 



Although the ton<i'uc 

 is wantinii". beiny re- 

 placed in K«iV])t l)y a 

 somewhat dirt'erentl}' 

 constructed plummet, 

 yet a fairly complete 

 weighin*^ ap})aratus has 

 now heen I'eached, since 

 th(» two ])rime recpii- 

 sites of small friction 

 and a position of the 

 a.xis of rotation some- 

 what above the line of 

 junction of the j)oints 

 of suspension of the 

 pans are both present. 

 That t)oth these condi- 

 tions must be fulfilled 

 in order that the scales 

 may work well, the 

 reader need not be in- 

 fornuHl. But whether 

 these important improvements may not have been adopted in the first 

 instance without any clear anticipation of their advantages is at present 

 left undecided. The monuments show that they were in fact adopted, 

 and weighing could be performed very well upon such a balance, \n-o- 

 vided the weigher were able to judge when the beam was horizontal. 

 In those days, however, as now, many persons were unable to do that, 

 and therefore a further improvement was called for. This was soon 

 supplied by the attachment of a linger or little stick at right angles to 

 the beam, which, passing across a line of some kind, whether in front 

 of it or behind it. or both, should point out any departure from the 

 position of equilibrium. This is what we call the tongue. It is shown 



Fig. 5. — From Baumeister's Monuments of Classical Aiiticinitv. 



