TIIK I'KNKlI.t'M. 



Tin' |M-iiiliiliiiii wiifl III" llie well known furni uw<l liy Bonlii uii<l iimiiv otlior« 

 anil <;<'ni'riilly known i\» " r>orilii's |icn(ln!inn ". It conttisls of» HplM'riiral Utll of 

 nx'tiil )ittarliL-(l iiy u lliin wiiv to h hiiiuII und sliort t vlin(k-r in wliicli tli«< kiiife- 

 «■ilj^e m f\\(^\ lit iif{lit-an<i;It's to its axi». On it |M>rtion of this cvlindt-r projc-ctinK 

 iiliove tli(> knil'f f(l;;c were the ii'ljustin«; screws liy means of wliicli this jurt of 



tlic a|i|>iiriitii8. exclusive of the wire and kill, ild In^ intwle to vilinit« in a 



lieriod closely approxiinatinj» to that of the |XMidnlnni ivs a whole. 



It was foiMidhytriallliat this adjust in<1)t milcht li<.'considenil)ly<lisl)irlx.«tl with- 

 out sensihly altcrini; llie iiiriod of the ixiidiilum. hut it was, neverlhelww, earefully 

 attended to in all of the e\|K'riin(nts. The aihanlime of nlakin^it is, of cour^«, 

 that it greatly simplifies the calculation of the rcduwHl lenyjtli of tho |ieuduluui. 



I.OCATION AND Si:Sl»ENSION OF TIIK PKNr)i:|.UM. 



The |iendulnm was swimg in oue of the small ro<^)ms of tho pliyi>ical labora- 

 tory which is so protected from sudden chaiige.s of tem|H.Taturc and from current« 

 of air ius to Im- especially snitalile for the piir|H>K«-. In this room is a lar-^e stone 

 pier aliout (50 cm. s<iiiarc in seclion, liuilt U)i..n a solid foundaliou and extending 

 to a height of alM>ut 2 metres. A heavy l»ar of iron alwut 70 cm. in length ami 

 having a cross-section of aUnit 1 1 cm. hy '2.5 cm. w.us placed on the top of this 

 pier and wa.s secured in its plju-i- hy means of heavy lilocks of stone whicli were 

 placed upon it. The end of the iron Uir projected just far enough to allow a 

 resting pla(;e for the plane upon, which the iiendulum was swung. The location 

 of the fienduluui was approximately a« follows; — 



latitude— N.-3rA4r 



I^ingitude— E.-139"-46' 



Height al>ove sea level .") metres. 



According to the original plan of this |tendulum the itali is to be uttjuhe«! 

 to the wire by means of a small cup the inside ol which is gmund to a nuliu» 

 e(iual to that of the IkiII. The cup is first fastentnl to the win; through a |>er 

 fonited screw head, and then a little tallow U-ing spread over the inside of the 

 cup the ludl adher(!S to it very readily. This is a very usiful deviw- in that it 

 makes it e.xsy to attach the ImiII in various jMwitions in order tli.it any lack <if 

 uniformity in \tn structure may U- delccteil. Having st-rved this pur|K>se, how- 

 ever, the cup was rejected, thus simidifying the calculations and leiwening the 

 prohidiility of error in the linear nieasun'mentj«. The Iwll wiis finally fastened 

 to the susjH'nding win' l>y means ..f .i sm ill drop of solder wiiich was fuwd to 



