21 



iifterwiUils 1-ciIucihI to tlie inidillo liy iii'mis ii|";i iiiicroinctric iiii'.u^iircnK.'iit of the 

 width of tlie line. 



1 



lilt.- 



No 



of 



olw. 



y 



ill lie of l> 



/ 



X. 



.\-. -M) 





4 

 :5 





(■.:•■ 



111' 2.S"..-) 

 „ 2;»".:'. 



i;.')(;i.(;4 









■ » 





11 



., 27". 



., .c.i 













it 



„ 21]". 

 „ 27". 











4 







., lT,"..; 



.. .t;i 



Miviii lit' 20 iilisovvations — 



/ = <^.")(;i.(;2 



Anotlier seric.'; of l'^ i)ioa<uivinents wa--^ inaih' in the S|i;\^triini of tho lirst 

 iikIit. ill whifli the liiw i.s mori" neatly defined and the set was made n|i(in the 

 ntiddli- id" th<' tiiKv 'I'lii' mean <d" the vesnlls aijrti's a'mnst e.vaetly uilli tin- 

 |ir<'ie lih'.^ Iieini; 



1), illld I), 



'I'jii's«? lino are nf (iucli IVi^inent ime in wave-lenrjth inea-^inenients as fnriiish- 

 in'.;, in the distanee which separates them, a sort of unit of cnn)|iari^on, that if 

 was tiion'^ht advisalili' to make a more extemh'd series of measnrenu'nts n[ion 

 tliem than npon any i>i" the oljiers. J), «liirli is that of «greatest wavedeni^th, 

 wa.s nii'a-nr'il din-rlly lnit tin' wave li'n'.;th 1>, w;i>. dcliTUiinid liy niiMUS nf 

 mi roiiH'tiM' ni'Msnri's lium li,. 



I), 



Date 



N. 



. of 



oIpS. 



V.l 



Ine 



of/, 



/ 





Nov. IS 





.s 





:,T 



2:V 



:',7".(; 



•>r" !• 



.".Sind 



.7'.! 



, Jl 





• > 



• > 







'» 



.ill li 



:!7" 

 :'.7".'; 

 :;7".<; 

 :tt;"7 





.77 



.7s 

 .7'.i 

 .7'.i 



.7S 



■'J 





■A 



:» 

 :\ 



.1 







'T 



:i7".'i 

 :!7".7 

 :n"2 

 :jc,",2 



•' 



.7K 



.71I 



.7S 



.7»; 



