Fuly 29, 1886] 
NATURE 305 
when a sufficient amount of open water appears, to make the 
passage a reasonable certainty, and the date for this year I 
place at from July 5 to 15, as it is more than likely that a 
ship could have got through the Straits in ten days. The ice 
is, moreover, so sensitive to wind that even if telegraph 
stations were so placed as to be able to convey to ships news 
regarding the position of the ice ahead, long before the ves el 
arrived at the place the condition of affairs might, and probably 
would, be totally changed. 
As to the closing of navigation in 1884, Mr. Laperriére 
reports, at Cape Digges, that on October 25 the ice was solid 
in every direction, and at Nottingham Island a similar entry 
is made on the 27th. A distinction must be made between 
the closing of navigation by the formation of young ice, and 
the presence of a large field of heavy old ice which is cemented 
together by the formation of young ice between the pans. In 
the first case any ordinarily powerful steamer could go through 
without risk, but in the second case the most powerful of the 
whaling or sealing steamers would be helpless. The western 
end of the Straits is always subject to incursions of this heavy 
ice, from Fox Channel, and especially so in the months of 
September and October, when strong north-easterly and north- 
westerly gales are frequent, and we have now evidence that in 
both seasons, 1884 and 1885, this heavy ice came down in 
October. 
As to the length of season for practical navigation, if we 
regard the presence of field ice as the only barrier, the infor.na- 
tion which we have got would point to the months of July, 
August, September, and October as being the months in which 
the Straits are passable. As a rule, in July there will be delays, 
but to vessels strengthened and sheathed there would be no 
danger in making the passage. 
All the inhabitants of the Labrador, the Straits, and the Bay, 
spoken to on the subject, agreed in stating that the ice move- 
ments this year were much later than the average; at Fort 
Churchill the season was fully a month late, and on the Labrador 
three weeks, so that I think it will be found that on the 
average four months will be the length of the season for practical 
navigation by steam vessels which would be freight-carriers. 
There have been, I am informed, seasons when the Straits were 
clear of ice in the month of June, but they are, according to 
the logs of the Hudson’s Bay ships, quite exceptional. Captain 
Hawes spoke of such being the case only once in his experi- 
ence of fourteen years, and the dates which I have seen of the 
arrival of the Hudson’s Bay vessels at their ports of destination 
show no arrival earlier than August. 
THE TRANSCASPIAN FAUNA 
E notice in one of the last issues of the Bzdletin of the 
Moscow Society of Naturalists (1885, No. 2) a most valu- 
able paper, by M. Zaroudnoi, on the birds of the Transcaspian 
region. His list contains an enumeration of 184 species, well 
determined on 600 specimens—doubts remaining only with 
regard to a very few species. The author distinguishes in the 
region the following chief zoological sub-regions :—(1) The 
Kara-kum desert, having a pretty well furnished flora, notwith- 
standing its immense sandy plains and salt clays. The Tamarix 
forests, now mostly destroyed, are well peopled with the AZva- 
Phornis aralensis, as also with a few Podoces (Panderi ?) and 
Passer (ammodendri?), which make their nests further north in 
the saksau/ forests. The Houbara quennii, Gray, is rare. The 
reptiles are represented by the Phrynocephalus interscapularis 
and feltoscopus, Agama sanguinolenta, Testudo, Naja oxiana, 
Eichwald; the Varanus sciueuws extends much further south 
into the Akhal-Tekke plain, and even to the Kopet-dagh 
Mountains. (2) The Akhal-Tekke oasis, striking by the monotony 
of its landscape, diversified only by the gardens of the Tekkes, 
which remain green even during the hottest part of the 
summer, when all vegetation is scorched up by the sun. In 
the plain only the Tamarix, a few willows on the banks of the 
rivulets, and the dark-green bushes of the capers, adorned with 
pretty flowers, are to be seen. The great areas covered with 
bushes of Alchag? camelorum and wormwood increase the 
monotony of the landscape. Pretty Fulodis variolarius, 
eufraticus, and sometimes g/obrcollis are often found flying 
around these bushes; in July the Fisheria baetica, Ramb., 
several Irises, as also Ampus fennicornis, Pall., several kinds of 
Ateuchus and Copris, and numerous species of Afelanozomate 
are met with. The stone-chatters (traquets) and Jarks are so 
numerous as to become troublesome. The Phrynocephalus 
helioscopus and Agama sanguinolenta fly at the approach of man. 
From time to time a dschetran, or a fox, may be perceived. The 
nights are sultry and hot, and one hears the shrivelling of the 
Grillus cerisyz, Serv., and G. capensis, Fabr., the barking of the 
jackals, and the cries of Cafrimalgus arentcolor, Sev. The 
banks of the few rivers, covered with brush and reed-grass, are 
the refuge of the wild cat and the Zagomys. The high summer 
temperature of the oasis is well known: 40° Cels. in the shade 
being not uncommon; and M. Zaroudnoi is inclined to ascribe 
to the great heat the intensity of the moulting of birds. The 
lark loses so much of its feathers that the body remains in many 
parts quite naked ; with the stone-chatters only the base of the 
feathers remains on their heads. Most of the birds met with in 
the oasis during the summer belong to the Aral-Caspian fauna, 
the others come from the mountains; these last have followed 
the courses of the rivers and have taken possession of the Akhal- 
Tekke gardens; such are the Saliczfasser montanus, Passer 
indicus, Sylvia mystacea, Butalis grisola, a great number of 
Salicicarte, and several others. Some, like the griffons, the 
ravens, the Cypselus apus, the Cheliden urbica, the Merops 
apiaster, inhabit the mountains, and descend to the plain only 
for hunting. The Galerita magna, Calandrella pispoleta, and 
Saxicola isabellina, may be considered as representatives of the 
Akhal-Tekke fauna owing to their considerable numbers. (3) 
The mountain-region is much more interesting, especially when 
the traveller reaches the upper valleys covered with forests, 
where the vines grow wild. Wild cats and jackals are the usual 
inhabitants of these valleys ; but the Cywat/urus jubatus and the 
Leopardus pardus are rare ; L. irbis is never met with in the 
region. //y@na striata is occasionally met with. Z//obis tal- 
pinus, several Erinaceus and Platycercomys, as also Histrix 
hirsutirostrix are common. The dreadful Vigera eufratica is a 
source of continual danger during the grape-harvest. vemias 
velox and Agama sanguinolenta are worthy of notice. As to 
the birds, we must merely refer to the list of M. Zaroudnoi, 
where notes as to their distribution are given in French. The 
zoological determinations have been revised by M. Menzbier. 
SOCIETIES AND ACADEMIES 
LONDON 
Royal Society, May 27.—‘‘ Researches in Stellar Photo- 
graphy.” By the Rey. Prof. Pritchard, F.R.S. 
The objects of these researches are :—(1) To ascertain, if 
possible, by means of definite and accurate measurement, as 
distinguished from impressions and estimates, what is the rela- 
tion between the diameter of a star-disk impressed on a photo- 
graphic plate with a given exposure, and its photometric 
magnitude, instrumentally determined. With this view, five 
plates of the Pleiades were taken with different exposures, on 
different nights. The diameters of the star-disks on each of 
the plates were then measured with a double-image micrometer, 
checked by measurement also with the macro-micrometer in the 
Oxford University Observatory. Curves were then drawn for 
each of the plates, taking the magnitudes as given in the 
** Uranometria Nova Oxoniensis ” as abscissze, and the measured 
diameters as ordinates. The result was a satisfactory coincidence 
in the case of all the plates, leading, when treated in the usual 
manner, to the final result— 
D- Di=8 flog M’-log M} . . . (1) 
where J, ’ are the measured diameters of any two stars on the 
plate, and JZ, M’ the corresponding photometric magnitudes ; 5 
being a definite constant depending on the physical circumstances 
of the particular plate. 
It was observable that, out of twenty-eight stars examined, 
three stood out from the rest, indicating, as might have been 
expected, some peculiarity in the spectra of these stars. In 
the memoir itself the tabular relations of all the measures are 
exhibited. The similarity of the symbolical form above to the 
relations existing between ‘‘ magnitude” and intensity of light 
is obvious and interesting. 
(2) Another branch of the inquiry is still more important, and it 
is this. Seeing that in the modern use of the dry plates the times 
of exposure are so considerable, and the processes of develop- 
ment and drying, &c., so suspiciously dangerous to the stability 
of the films, it becomes a matter of great importance to ascertain 
