August 20, 1891] 



NATURE 



391 



A PROFITABLE industry, little heard of, is carried on among 

 the hills of Connecticut {Sci, Am.). It is the manufacture o 

 birch oil, which is used largely for confectionery, and gives a 

 perfect wintergreen flavour. There are eight mills in the State 

 — the first built only ten years ago. Birch brush, without 

 foliage, and not over 2.7 inches in diameter, from the black, moun- 

 tain or sugar birch (not the yellow or white), is chopped up and 

 boiled with water in tanks. The steam, passing through an 

 iron pipe near the top, is condensed in a coil immersed in 

 running water, and drops into a glass jar. The oil is much 

 heavier than water, and in the crude state is of copper hue. 

 The mills work only from October to April. A good deal of 

 adulterated birch oil is used in tanning leather to imitate Russia 

 leather. 



We have just received the Report for 1890 of the Botanical 

 Exchange Club of the British Isles. There are about fifty 

 members, and a list of the plants that are wanted is sent out 

 every spring. The Secretary is Mr. Charles Bailey, Ashfield 

 College Road, Whalley Range, Manchester. The distributor 

 for last year was the Rev. E. T. Linton, one of our most pains- 

 taking British botanists, and the Report is edited by him. The 

 number of specimens received was 4100, from twenty-six con- 

 tributors. The most interesting novelty of the year is an 

 Arenaria found at the head of Ribblesdale, in York.shire, which 

 is nearly allied to, but not quite identical with, A. norvegica, 

 known only within the British area in the Shetland Islands and 

 Orkney, and A. cilicta, known only in County Sligo. Mr. 

 Linton treats it as A. gothica, Fries., but that plant is an 

 annual, whilst the Ribblesdale plant is a perennial. It is, in 

 fact, a form about half-way between norvegica and gothica. 

 Out of thirty-eight pages of the Report, eleven are occupied by 

 Rubi. A new general working up of the British Rubi is much 

 wanted, and it is evident the different referees to whom the 

 specimens have been sent do not use some of the names with 

 the same application or ran^e of significance. What beginners 

 want are good typical specimens of the most distinct forms. To 

 give them the intermediate connecting links before they know 

 thoroughly the typical sub-species only bewilders them. In 

 roses the difficulty is that it is often impossible to determine a 

 given plant positively without seeing it in three stages — flower, 

 young fruit, and mature fruit — and nearly all the specimens sent 

 to the Club arrive in a single stage. The above remark applies 

 to R. mollis and toinentosa, concerning which there are eleven 

 paragraphs in the Report, none of which tend to any real en- 

 lightenment. To Hieracia the same remark applies as to Rubi ; 

 but Mr. F. A. Hanbury's elaborate monograph, now fairly started 

 off, will put this right. Three other sets of plants are at present 

 receiving much attention from the members, i.e. hybrid willows, 

 hybrid Epilobia, and Potamogetons. At the end of the Report 

 there is a long list of new county records. 



The additions to the Zoological Society's Gardens during the 

 past week include a Brown Capuchin {Cebus fatuellus ?) from 

 Guiana, presented by Miss Phyllis Duncan ; a Red-bellied 

 Squirrel (Scinrtts rariegatits) from Trinidad, a Golden Agouti 

 [Dasyprocia nguti) from Guiana, a West Indian Agouti [Dasy- 

 procta cristata) from the West Indies, two Violet Tanagers 

 {Euphonia violacca) from Brazil, presented by Mr. R. J. L. 

 Guppy, C.M.Z.S. ; a Common Otter {Ltttra vulgaris), British, 

 presented by Mr. D. E. Cardinall ; a Marbled Polecat {Putorius 

 sarmaticus) from Quettah, presented by Colonel C. Shepherd ; 

 a Vulpine .Squirrel {Sciuriis vulpinus) from North America, 

 presented by Miss Pickford ; seven Lemmings (Myodes letnmus) 

 from Norway, presented by Mr, T. T. Somerville ; two Sparrow- 

 Hawks {Accipiler nisus), British, presented by Mr. Digby F. W. 

 Nicholl, F. Z.S. ; a Grey Parrot {I'sittacus erithacus) from 

 West .'\frica, presented by Mrs, Hale ; a Golden Eagle {Aquila 

 NO. 1 138, VOL. 44] 



chrysaHus), European, presented by Captain Taylor ; a Common 

 Chameleon (Cham<Tl<OH vulgans) from North Africa, a Dwarf 

 Chameleon {Chamaleon puiniliis) from South Africa, presented 

 by Captain Wood ; two Common Chameleons {Chamceleon vul- 

 garis) from North Africa, presented by Mr. E. Palmer ; an 

 Egyptian Ichneumon {flerpesies ichnmmon) from Spain, a Black- 

 headed Caique {Caica viclanocephala) from Demerara, deposited ; 

 a Yak {Poephagus gntnuiens), born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 

 Pertodic Variations in the Latitudk of Solar 

 Prominences. — From a paper by Prof. Ricco, in Comptes 

 rcndtts for August 3, it appears that the mean latitude of solar 

 prominences varies periodically in the same way as that of spots. 

 During the last eleven years observations of the form, position, 

 and dimension of solar prominences have been made at Palermo 

 on 2207 days, with the same refractor and spectroscope. In this 

 period 7663 prominences have been observed, having a height 

 equal to or greater than 30". Neglecting a few irregularities, 

 the observations show that about the time of maximum solar 

 activity prominences occur nearest the sun's equator ; the mean 

 latitude for both hemispheres in the second year after the last 

 maximum being 27°'5. There is then a rapid general increase 

 in the latitude of most frequent occurrence up to the minimum 

 epoch, the mean latitude for both hemispheres in the year follow- 

 ing the last minimum— that is, in 1890 — being 4i°*3. In other 

 words, up to the commencement of the mmimum period pro- 

 minences approach the equator. They then appear in high 

 latitudes, to descend again to the equator in an eleven-year cycle. 

 The intimate relation that exists between this variation and that 

 observed in the distribution of spots is evident from an inspection 

 of the accompanying figure, which represents the mean latitudes 



of spots according to Prof. Sporer's observations, and those 

 found for prominences by Prof. Ricco. The pairs of like curves 

 run almost parallel to each other, and are separated by an 

 approximately equal number of degrees at all points. It is 

 worthy of remark that the photographs of the solar corona 

 recently investigated by Prof. Bigelow exhibit a movement in 

 latitude which is most probably connected with the latitude 

 variations of sun-spots and prominences. 



Photography of Solar Prominences and their 

 Spectra. — In the American Journal of Science for August, and 

 Astronoviische Nac/trichlen, No. 3053, Prof. G. H. Hale gives 

 some results which he has obtained in solar prominence photo- 

 graphy, utilizing the methods noted in Nature, vol. xliii. 

 p. 133. With the fourth-order spectrum of a grating having 

 14,438 lines to the inch, and both radial and tangential slits, the 

 broad II and K lines invariably have bright lines running through 

 them, apparently to the top of every prominence. This is an 

 important fact, for the position of H and K in the spectrum 

 makes it unnecessary to stain the photographic plates, or prolong 

 the exposure, as would be the case if the C line were employed ; 

 and their characteristic banded appearance renders them pecu- 



