TIDl'.S IN MrMURDO SOlfND .(S; 
would have hccu ruiiu'd l>\' t r\s(als ol icc- lormiiif; aiul 
spoiling all tin- iiKut- dcliralr s|>('i-inu'ns. 
Tlic jilivsical t:niulil ions under vvlnrli iIk'S<' diillini;; 
or plankton origan isms cxisl is ol ^rca 1 inipoi"(anc\', 
and observations were regularly laken vvilli this end in 
view. 
'I'lie Mxpedilion was lorlunale in possessnig some veiy 
fine reversing I lierniomel ers made by Rielifer ol Uerlin, 
and these were used lo deleruime (lie lempeialure ol ihc 
sea. I)uring llie vvmlcr a reversnig water- hoi tie was used 
lo obtain samples of sea water loi" anal\ sis, but vvi t li 
what suetcss (.annot be aseerlamed until I he analyses 
have lieen eairied out. 
During the wmt er onlv one sample could be taken 
each day, as tlie instrument had to be taken ba( k to llic 
hut, thawed out, and thorougldy dried. 
Soundings were also taken through erachs and seals' 
bl(Jw-holes, and these will b<" plotted on llie charts. 
During liu' fust year a complete recoid was obtained 
with an automatic t itle~ga u;?e < oust nu t<'d and looked 
after by Mr. Day. It might be mentioned Imre that tlie 
McMuido Sountl tides present, some unusual lea 1 u res. 
wSj)ring tides and nea|) tides aic (|nile masked by the 
d iu rnal inetpialit y o( heigh t s, depend mg on I he (h'( lina I ion 
of the moon. i''or exam|>le, witli high de{linations N. oi" 
S. the greatest rise and lall takes plat and there is only 
one high water and one low water m I he t wenty loui' luturs. 
Hut with the moon uw llie e(|umo( lial there is miu h less 
rise and fall, and two higli waters and two low watery 
arc experienced, 
