TRANSIT OF VENUS 325 
to each original pair of fronds, the whole being surrounded by 
one mass ; nor could any pairs of zygospores be detected as be- 
longing to any particular four fronds. Yet, if the fronds begin 
by dividing, (and this is pretty clear) each original pair of fronds 
must produce two zygospores, as in C. Ehrenbergit. 
The paper concludes with a nominal catalogue of all the 
species and varieties of Desmidieze (110) known to the author as 
mentioned occurring in New Zealand. 
W. M. MASKELL. 
THE TRANSIT OF VENUS. 
DUNEDIN. 
The observations of the transit at Dunedin were a great suc- 
cess, The morning broke, indeed, with a very unpromising look, 
and until about 6.30 0 ‘clock the prospect of observing the critical 
points of the transit, or even of seeing it at all, seemed hopeless. 
But a little before 7 o’clock the sun showed his face, and though 
clouds continued at intervals to pass, there appeared good rea- 
son to hope that the “contacts” might be observed after all. 
The event abundantly justified this expectation. In fact the 
light film of cloud that throughout obscured the sun was a cir- 
cumstance of the most favourable character. Itgave remarkable 
steadiness and distinctness tothe observations. At zxzternal con- 
tact there was so little of that agitation known as “ boiling,” that 
the range of uncertainty in fixing the instant of internal contact 
I myself set down as being not greater than perhaps two or three 
seconds. I was reassured on this point on finding that Mr. Be- 
verley, in his communication to the Evenzng Star, makes a simi- 
lar observation. 
I shall be surprised, when the observations are collated (unless 
the “ personal equation” turns out to be unusually disturbing), 
if the times of observation of internal contact by the several 
Dunedin observers do not come within two or three seconds of 
absolute synchronism. When it is remembered that two seconds 
of time only indicate an angular separation of one-tenth of a 
second of arc (a quantity inappreciable except by the finest tele- 
scopes in use), it will be seen that this result is wonderfully 
satisfactory. 
None of the observers in Dunedin make any mention of 
having seen either “ligament” or “black drop ;” the “first ap- 
pearance of well-marked and persistent discontinuity in the illu- 
mination of the apparent limb of the sun near the point of con- 
tact,” being recognised with almost geometrical distinctness. 
In regard to the erternal contact I shall be prepared to find 
a considerable difference between the several observers. The 
phenomenon is a most difficult one to observe, and, I should 
imagine, under the most favourable circumstances, would give a 
