April 23, 1874] 



NATURE 



485 



after having looked in vain for their hive in its old place. At 

 night I picked the exhausted bees up, and, having restored warmth 

 to them (by leaving them for a time upon my coat-sleeve), I 

 returned them to their companions. 



Here was an illustration that the faculty of memory was supe- 

 rior to that of obstrvnticn ; but that was not all. Nearly every 

 bee which I picked up during the twenty-three days through which 

 this effort of memory lasted was an old one; as was easily deduced 

 from observing the worn edges of the wings : showing that, whilst 

 the young insects were quick in receiving new impressions, and 

 in correcting errors, the nervous system of the old bees continued 

 acting in the diyection whieh early habit had affected. So true is 

 it that " One touch oC iVature makes the whole world kin." 



Marlborough House, Torquay John Topham 



Pollen-grains in the Air 



Will you allow me to ask Mr. Hubert Airy, in reference to 

 his interesting paper on the "Microscopic Examination of Air," 

 in Nature, vol. ix. p. 439, on what ground he refers the 

 "triangular pollen" captured on his slide to the birch and 

 hazel ? Observations of my own have led me to the conclusion 

 that the pollen of plants which depend exclusively on the wind 

 for their fertilisation is perfectly spherical, at all events before 

 the form of the grain is disturbed by the emission of the pollen- 

 tubes, and this indeed one might expect from (J priori considera- 

 tions. Among the pollen-grains I have especially observed, are 

 those of Corylus avellana, Pelida alba, and Populus bahaniifera. 

 I shall be much obliged if any of your readers could refer me to 

 any accurate published description of the form of pollen-grains 

 beyond those contained in Fritzsche's " Beitriige zur Kenntniss 

 des Pollen." Alfred W. Bennett 



6, Park Village East, N.W. 



Lakes with two Outfalls 



I A^r a little surprised to find, by the recent letters in your 

 paper, that Science makes so wide a mouth over tliis phenome- 

 non, though its exceptional character, and the general correct- 

 ness of Colonel Greenwood's theory, must readily be recognised. 

 My surprise is occasioned by the fact that Norway, which is now 

 visited by thousands of educated English tourists every year, can 

 supply, not one, but several, I had almost written many, apparent 

 examples of this double outflow. I have not myself passed the 

 watershed at the Lesjeskaagen Lake, though I was close to it in 

 August last, and would have examined it if I had known its im- 

 portance ; but I know enough of the locality to think that 

 Colonel Greenwood is probably right in his explanation of it. 

 But there is another, which I have passed, and which is situated 

 on perhaps the most frequented route in Norw.ay, viz. that from 

 Lxrdalsoren over the Fille FjeW, to which I hardly think the 

 same explanation would apply. Between Nystucn and Skogstad 

 is a chain of lakes crossing the watershed, the highest of which 

 (not the one marked on the Vei-cart over Norge, I think) sends 

 its waters to the west, past Nystuen to the Sogne Fjord, at L^erdal- 

 soren, and on the east by the Lille Mjosen, and Aadalen to the 

 Tyrifjord, and so past Lirammeu to the Christiania Fjord. This 

 lake is a small one, and the double outflow is close to the high 

 road. I cannot imagine any commercial object for an artificial 

 cut, and it must be well known to hundreds who annually pass it. 

 The Vei-cart shows several other instances, I know not how au- 

 thentic, though I have always found it fairly accurate, erring rather 

 by omission than commission. But in lat. 62° N., long. 24* 

 40' E. or thereabouts, is a very remarkable watershed, having a 

 complication of outfalls; the Bredals-Vand sending one to the 

 N. \V. to the Geiranger Fjord, and a second to the Vaage-Vand 

 and GudbrandsJalen ; which is also joined by a draft frcm a lake 

 to the S.W., which likewise sends a feeder to the Opstiyen 

 Vand, and 50 W.S.W. to the Nord Fjord. This I have not 

 myself seen, but I was at Merok on the Geiranger for some days 

 last August, and was assured by my landlord that the map was 

 correct in this particular. As the Norwegian peasantry are well- 

 educated, intelligent, and truthful, and this route forms their 

 regular short cut to Christiania, I cannot doubt but that it is the 

 fact. However, I have engaj^ed to go over the track this 

 summer with Captam Uaht, the well-known jolly commander of 

 the Erkno, and I will take care to ascertain the truth and report 

 the result. If, moreover, there are any geological or geographi- 

 cal po.nts to be attended to, and Colonel Greenwood w'ill 

 kindly furnish me with instructions, I shall be happy to attend 

 to them. 



I have a strong recollection of having passed two or three 

 cases of double outfall on a small scale in my wanderings ; but 



not having been aware of the importance of the point, I did not 

 take notice sufficiently precise to enable me now to put my finger 

 on them with certainty, but my general conviction is strong, 

 that Norway can furnish several, if not many examples, which 

 are the more significant from the fact that it is one of the oldest 

 countries in the world. W. B. Thelwall 



Burghley Road 



Will you permit me to correct a mistake as to a matter of 

 fact in Natdre, vol. ix. p. 441. Loch-na-Davie, Arran, has two 

 outlets, as is correctly represented in the Ordnance Map, and 

 also in that in Bryce's "Geology of Arran." In August 1872 I 

 walked up the norlh stream from Loch Ranza to its outfall from 

 Loch-na-Davie. I think Colonel Greenwood ought at least to 

 have made himself acquainted with the Ordnance Map. 



Edinburgh A. Craig Christie 



THE "CHALLENGER" EXPEDITION* 



IV. 

 Tristan d'Acunha 

 A MONGST the places in the Atlantic marked out by 

 -'*• the Circumnavigation Committee as being of espe- 

 cial interest, the small island of Trinidad is noted with 

 those whose vegetation is absolutely unknown, or all but 

 so. From this fact Trinidad became a point of attraction 

 which Mr. Moseley was most anxious to reach. Owing, 

 however, to unfavourable winds and other causes, as well 

 as to a desire of those in command of the ship to pro- 

 ceed south, the visit to this little island was abandoned, 

 with the hope of calling there on the return voyage. After 

 a narrow escape, also, of missing Tristan d'Acunha, the 

 vessel anchored on the north side of the island, and the 

 morning was spent in searching the low lands under the 

 cliffs, SCO feet being the greatest height that was attained 

 during the stay. On this side the island rises in a range 

 of perpendicular cliffs of black volcanic rock, in appear- 

 ance somewhat similar in structure to that exposed in 

 section in the Grande Cural in Madeira. At the base of 

 the cliffs here are acbiis slopes, and a narrow strip of low 

 shore land of an irregular rocky and sandy nature. The 

 settlement lies on a stretch of low land, broader and 

 more even, and extends westward. The ascent to the 

 plateau above the chffs is comparatively easy, owing to 

 the deep gullies by which the cliffs are broken. 



Though the extent of the island is small, its actual area 

 being not more than 16 square miles, the botanising was 

 confined to the irregular strip of shore land just alluded 

 to, and to the gully immediately above the settlement. 

 Further exploration would have been made, but a sudden 

 squall coming on, the recall was hoisted from the ship, 

 and the party had to leave the island, after a visit of only 

 six hours. Grasses, sedges, inosses, and ferns grow on 

 the cliffs, and occasional patches of Phylica arboifa Th., 

 a rhamnaceous tree peculiar to the islands, as well as a 

 species of Eiiipctrunt ; these plants, however, are mere 

 prominent towards the summit. At the foot of the water- 

 courses under the cliffs are bright green patches of Riiiiicx 

 fnitcsccns Th. Mosses and liverworts cover the lower 

 part of the cliffs, and the latter also abound beneath the 

 grass in some situations to such an extent, indeed, as to 

 cover the earth as with a green sheet. Spaitiiia arundi- 

 nacca Carm., grows in rounded tufts amongst the other 

 herbage, and in the clefts of the rocks was seen in 

 abundance Asphiiii/m old it sat 11 in Forst., and Loiiiaria 

 alpina Spreng. It is remarkable that the plants oi Loinaria 

 when found in stony places, and in a comparatively starved 

 condition, were mostly furnished with fertile fronds, 

 whilst those growing in rich vegetable mould were barren. 

 Amongst flowering plants the most common were Apiuiii 

 australe Th., I'ehiigohiuiii austrak Jacq., Soiiilius 

 oleraceiis L. our common annual sow-thistle, HyftK/iaris 

 glabra L. a closely allied plant to the sow-thistle, and 

 also found in many parts of England. A cinchonaceous 

 plant, Ncrtcra dcprcssa Banks, was very abundant, and 



♦ These Notes are founded on letteri sent home by Mr, H. N. Mosely. 



