328 



NATURE 



{Feb. 25, 1875 



not a thermometer with me). It was a warm summer's day— 

 July 23. The ice exhibited the usual prismatic structure, but th^ 

 prisms seldom exceeded a third of an inch in diameter. I was 

 informed tliat in winter it was choked up with snow. The other 

 fissure also contained ice, but as it was less accessible, and 

 seemed in no way different from the former, I did not enter it. 

 The especial interest of this case is that it affords what I might 

 call the most rudimentary type of a ghicure ; a natural ice- 

 house, replenished every winter, and perhaps sometimes entirely 

 cleared out during an unusually hot summer. The "Grotto" 

 ou Monte Tofana, near the Ampezzo Pass (which I have not 

 been able to visit), is, I expect, another of this kind. 



St. John's College, Cambridge T. G. Bonney 



[By a misprint " glacier " was put for glaciive in'_the last para- 

 graph of Mr. Ward's paper. — Ed,] 



The Morse Code 



The folloviring mr.emonical device may be of some use to 

 young telegraph students, and others, who wish to commit the 

 Morse alphabet to memory. There is, I believe, a device em- 

 ployed in the Government schools, but it gives one so little help 

 that I lately jotted down the subjoined scheme for my own in- 

 struction. 



Let the vowels a c i n and also s h represent the dots, and 

 the remaining letters ol the alphabet the dashes in the Morse 

 code : the word attached to each letter will then express the 

 signal for that letter. These words must be learnt ; a task 

 rendered easy by their commencmg with or containing the letter 

 they signify. 



A few of the letters, c.f;. J (the word for which might be re- 

 garded as a new way of spelling Ujiji), O, and Q, present a little 

 difficulty, which some of your readers may lessen. As it is, 

 these exceptional cases are so quickly impressed on the memory 

 that the code thus learnt can be written in a surprisingly short 

 lime, and read soon afterwards. It is hardly possible the plan 

 here suggested can be new, yet, as I have not met with anything 

 similar, I venture to send it to you for publication. 



\V. F. Barrett 



The Miciographic Dictionary — Pollen Grains 



At present I have to do with the **Micrographic Dictionary" 

 and the two other woiks mentioned in my letter printed in 

 Nature, vol. xi., p. '2S6. If the pollen grains of Mimulus nws- 

 (hatits are variable (as now stated by Mr. Cooke on the authority 

 of Dr. Mohl), how is it that llie figures and descriptions in the 

 books mentioned are all alike ? There is no variability here, but 

 wonderful sameness both in illustrations and letter-press. 



As the accuracy of my first simple observation has been called 

 in question, I will add another. In the " Micrographic Dic- 

 tionary," PI. 32, Fig. 28, is given the pollen of Sonchus pains- 

 tiis. This, like that of the Mimulus, is totally wrong, the reticu- 

 lation is by no means correct, and the abundant spines with 

 which this pollen grain is clad (so common in the Compositas) 

 are totally omitted. Now, on turning to the Rev. J. G. Wood's 

 book, PI. 3, Fig. 24, this erroneous figure is reproduced with 

 incorrect reticulation and no spines, and on referring to Mr. 

 Cooke's work, PI. 2, Fig. 6, the same errors are again perpe- 

 trated. W. G. Smith 



OUR ASTRONOMICAL COLUMN 



fi AND f- Reticuli.— These stars of about the sixth 

 mngnitude appear to offer a similar instance of large and 

 nearly equable proper motion to the well-known one 



afforded by 36 Ophiuchi and 30 Scorpii, which was first 

 pointed out by Bessel in the " Fundamenta Astronomias." 

 If we compare Lacaille's positions (taking them from the • 

 reduced catalogue published by the British Association) 

 with those given by the late Capt. Jacob from the Madras 

 observations 1853-57, we find with the Pulkova preces- 

 sions — ■ 



Secular Proper Motion. Direction of 



R,A. N.r.D. Arc of gre.it motion. 



C ... +237"-5 -"74"-9 i3o"'3 S4°-9 



f^ ... -f238"7 -79 '-6 133 '-S 53°-4 



The introduction of Brisbane's places would only 

 modify the above figures in a. trifling degree. 



When competent observers in the southern hemisphere 

 are provided with heliometers for research on stellar 

 aarallax, there will be no lack of objects to occupy their 

 pttention, and we may expect most important results from 

 such investigations. 



The Binary Star tj Cassiope.^.— We may very soon 

 be able to make a fair approximation to the orbit of this 

 double star, and so, with Mr. Otto Struve's value for the 

 annual parallax, form some idea of the real dimensions 

 and mass of the system, as is already the case with a 

 Centauri and 70 Ophiuchi. An orbit given by Mr. Powell, 

 of Madras, in vol. xxi. of Monthly Notices, R. A. S., is pro- 

 bably vitiated by typographical error or errors. Struve's 

 parallax is o"'i54 +o"'045. 



The Binary Star a Centauri. — According to Mr. 

 Powell's last elements, which are founded on measures 

 up to 1870 inclusive, the components, at the present time, 

 are nearly at their minimum apparent distance (i"'2), and 

 the angle of position is advancing at the rate of 10' 

 monthly. It may be hoped this fine object is receiving 

 due attention from astronomers in the southern hemi- 

 sphere at this critical period of the revolution. There 

 would appear to be no probability of such difficulties 

 attending observations at the passage of the peri-astron 

 as those presented by y Virginis in 1836, so far at least as 

 can be judged from the measures to i S70. 



Red Stars. — Amongst the red stars notified by the 

 late M. Chacornac, is one which he estimated between 

 the seventh and eighth magnitude, and of which he says, 

 " eclat tcrne et nebuleuse." The position assigned iden- 

 tifies the star with No. 11 72 of Riimker's Catalogue, 

 whence for the commencement of the present year its 

 right ascension is 4h. i6m. i6s., and polar distance 

 67° ig'7. Riimker calls it a sixth magnitude, and Arge- 

 lander (Durchmusterung) an eighth. Although different 

 eyes will not always agree in estimations of brightness of 

 the ruddy stars, there appears here to be a suspicion of 

 variable light. Another of Chacornac's isolated red stars 

 he himself indicates as variable. It is Oeltzen 21356, 

 called 6 mag. by Lalande (No. 41453), 5-6 by Argelander, 

 5 in the Washington Zone, 184S, July 24; while Chacornac 

 remarks, " sometimes brighter and sometimes fainter than 

 a star of the seventh magnitude near it," which is probably 

 Oeltzen 21386. Position for 1875, R.A. 2lh. 17m. 5s. ; 

 P.D., 111° 22'7. Neither of these stars is in Schjellerup's 

 Catalogue, but that list is very far from being a com- 

 plete one. 



Encke'S Comet. — The extreme faintness of this comet 

 at the present appearance is attracting the attention of 

 astronomers who have had most experience of the circum- 

 stances of previous returns. Last week we quoted the 

 remark of M. Stdphan on this subject, and we learn from 

 him that he was using a newly polished mirror in the 

 great Foucault telescope of the Observatory of Marseilles. 

 In 1868 and 1S71 the comet's appearance was very similar 

 to what it had been in previous years under analogous 

 conditions. In discussing the probability of any real 

 change in the comet's constitution, it may, however, be 

 well to bear in mind that in the year 1842, when the peri- 



