38 



NATURE 



[Nov. II, 1875 



sible, I trained a wasp to come to some honey which I placed in 

 a box communicating with the outside by an india-rubber tube 

 six inches in length and one-third of an inch in diameter. She 

 came to this honey continuously for three days, during which 

 time no other wasp found the honey. As regards colour, I 

 satisfied myself, by experiments like those made with bees, that 

 they are capable of seeing colour, though they appear to be less 

 influenced by it than are bees. 



OUR BOTANICAL COLUMN 



Irish HepatiC/E. — S. O. Lindberg has just published a 

 quarto memoir on the " Hepaticte in Hibernia mense Julii 1873 

 lectae." This memoir is a reprint from the tenth volume of the 

 "Acta Societatis Scientiarum Fennicse," and contains a list of 

 eighty-nine species of Hepatica; collected during a month's visit 

 to Ireland. The author had the benefit of the great geographical 

 knowledge of Dr. Moore — the author with A. G. More of the 

 "Cybele Hibernica" — to enable him to visit, without delay, the 

 most products vt > ortions of Ireland ; otherwise it may be doubted 

 if his collections would have been so rich. Many of the species 

 described are v ry rare ; some of them are new. The synonymy 

 of the species is worked out in a manner worthy of the greatest 

 praise. Many of the smaller forms among Lejeunea and other 

 genera are described from fresh specimens or from those preserved 

 in alcohol. The collections were chiefly made in Killarney. Of 

 the new species we may mention Lejeiitiea patens, L. Moerei, 

 Zygodon arista tus. In an appendix we find a list of the genera 

 of European Hepaticse classified as follows : — 



1. Marchantiacese. 



2. Jungermaniacege. 



3. AnthoceroteK. 



The group of March ant iaceae is divided into A. Schizocarpce and 

 B. Cleistocarpec? (this latter includes such genera as Tessellina 

 and Riccia) ; that of Jungermaniacea^ into the same two sub- 

 sections ; and these are again much sub-divided. 



The existence in Ireland of so large a number of interesting 

 forms, of which so very much yet remains to be known as to 

 their life-history, ought surely to act as a stimulant to the rising 

 school of Irish botanists. 



Marine Alg/E of the United States. — Although nearly 

 twenty years have elapsed since the third part of Harvey's 

 " Nereis Boreali- Americana " was sent to the press, yet the contri- 

 butions to a knowledge of the North American Algae have been 

 but few. W. G. Farlow, one of Prof. Asa Gray's assistants, 

 ascribes this to the fact that but few American botanists reside 

 on the western coast of America, where novelties might be ex- 

 pected ; and he publishes a most welcome list of the marine 

 species of the United States proper, not including Alaska, but in 

 part enumerating those of Vancouver's Island. Those added 

 since the publication of Harvey's "Nereis" are denoted by a 

 star. The number of species enumerated is 430, a number that 

 doubtless will be increased when the Algse are investigated as 

 recent lorms either living or preserved in fluid, and not, as is 

 now fre(^uently the case, only examined when in a state of what 

 is but little better than that of stains on white paper. Mr. Far- 

 low's list V ill be found in vol. x. 2nd sen of the Proceedings of 

 the Ameri.an Academy of Arts and Sciences. 



Coffee in Dominica. — A good deal of attention has been 

 directed of late to the island of Dominica as a coifee-pro- 

 ducing country, a fact briefly referred to in Nature, vol. 

 xii. p. 173. At one time coffee was one of the staple pro- 

 ducts of the island, and was grown not only in large quan- 

 tities, but also of excellent quality. At the present time little 

 or none is exported to Europe, but the island still grows 

 sufficient to supply its own demands, and we believe sends a 

 little to the neighbouaing islands. This falling off in the cul- 

 tivation of the coffee-plant, in a soil and. climate which experience 

 showed was eminently suited to it in every respect, was due to 

 the extensive destruction of the plants by what was then known 

 as the coffee blight. This was soon found to be of insect origin, 

 but no active or energetic measures were taken to rid the island 

 of the pest, which continued its ravages, destroying many plan- 

 tations, and even driving planters away in great numbers. 

 Nothing seems to have been known regarding the insect itself 

 until within the past few weeks, when specimens in their various 

 stages, together with the injured leaves, have been received at 

 the Kew Museum. Upon submitting these specimens to an 

 entomologist, they were at once identified as the White Coflfee- 



leaf Miner {Cemiostoma coffeellum, Mann.), an insect exceedingly 

 destructive to the coffee-plants in Brazil, Rio Janeiro, Martinique, 

 &c. The crops of coffee in Brazil are said to be lessened one* 

 fifth in consequence of the ravages of this insect. 



It is remarkable that little seems to have been known in 

 Dominica about the classification or habits of the insect, though 

 it made its first appearance there in 1833, some forty-two years 

 back, and it seems to have been known in Brazil only within the 

 last twenty or twenty-three years. An elaborate description of 

 the insect and its ravages will be found In the American 

 Naturalist^ vol. vi. pp. 332, 596 ; 1872. 



SCIENTIFIC SERIALS 



Annual Report and Proceedings of the Belfast NaturaliUs' 

 Field Club, 1873, 74- — This Report was written before the meet- 

 ing of the British Association in Belfast last year, so that its 

 issue must have been very much delayed. The Society, accord- 

 ing to the Report, as to financial condition and number of mem- 

 bers, is in a thoroughly satisfactory condition. The Society, as a 

 Field Club, makes excursions during summer ; an account of 

 those for 1873 is contained in this part of the Proceedings. The 

 papers read during the winter session are all interesting ; we 

 have space only for the titles : — " On the British Associ- 

 ation, its aims and objects," by Mr. W.Gray; "On Pro- 

 gressive Development," by Mr. G. Langtry ; " On the Surnames 

 of the Inhabitants of the County Antrim, and their indications, " 

 by the Rev. E. M'Clure ; " On Flints, and the Foraminifera, 

 Entomostraca, &c., contained in them," by Mr. Joseph Wright, 

 F.G.S.; "Irish Cranoges and their contents," by Mr. F. 

 Wakeman ; ' ' Notes on the Aurora Borealis, taken in Belfast 

 in the years 1870, 71, with suggestions as to its source and that 

 of the earth's magnetism and magnetic currents," by Dr. T. H. 

 Keown, R. N . The Appendix contains two valuable lists ; first, 

 of the Mosses of the North-east of Ireland, by Mr. S. A. 

 Stewart ; and second, of the Cretaceous Microzoa of the North 

 of Ireland, by Mr. Joseph Wright, F.G.S., the latter illustrated 

 by a large number of figures. 



Poggendorff^s Annalen der Physik und Chemie, No. 9, 1875, 

 — This number commences with a long paper, in which M. 

 Wilhelm Weber investigates mathematically the motion of elec- 

 tricity in bodies of molecular constitution. Among the points 

 treated are, objections against the fundamental law of electric 

 action ; identity of the moveable parts (in all bodies) whose move- 

 ment is heat, magnetism, or galvanism ; identity of vis viva of 

 the electromotive force in the current with the heat produced bf 

 the current in the conductor ; movement and distribution of 

 electricity in conductors ; and Kohlrausch's theory of thermo- 

 electricity. — In an article on formation of sound. Prof. Stem 

 inquires why tuning forks without resonant supports give such 

 a very weak sound. It cannot be due, as many physicists sup- 

 pose, to their less surface of contact with the air, else high-pitched 

 small forks could not sound louder than low and large ones, nor 

 could overtones sound louder than ground tones when e.g. 

 a large fork is struck with a hard body. Having shown reason 

 for thinking that the amplitude of vibratfon and number of vibra- 

 tions in unit of time have no direct influence on the strength of 

 the sound, Prof. Stern groups together a number of interesting 

 phenomena bearing on the subject : the difference in rate of 

 decrease of sound, in high and low forks, on withdrawal from 

 the ear ; a like difference with regard to transverse vibrations 

 and those produced longitudinally ; the interference-effects 

 where resonance-cases act on each other ; the effects of 

 bringing a resonator near an organ-pipe, &c. The paper 

 is not yet concluded. — The action of the Holtz machine still 

 requires some elucidation, and in a paper to the Berlin Academy 

 (here reproduced) M. Poggendorff furnishes "further facts 

 towards an adequate theory of electric machines of the second, 

 kind" (with two moveable discs). One of these facts is as 

 follows : — The two discs turning in opposite directions, stop 

 (say) the front one by holding it (the screw having previously 

 been loosened) ; then, when the back disc is rotated, a cur- 

 rent is obtained as before. Now turn the front disc round F 

 through 360°, and rotate the back disc as before. If this j 

 turning be done in the direction of the front disc's former 

 rotation, the current in the back disc is unaltered ; but if 

 in the opposite direction, it is reversed. A turning of iSo" 

 or even of 90° has the same effect. These and similar facts, 

 indicating an influence of direction (rather than extent) of dis- 



