March 7, 1895] 



NATURE 



441 



Lincei, December l6, 1894). The latter estimate is obtained 

 from the times furnished by magnetic or astronomical observa- 

 tories, possessing instruments capable of recnriing long-period 

 oscillations only. The instruments of the Italian seismic ob- 

 servatories, on the other hand, registered the rapid movements 

 travelling with the greater velocity, as well as the longer oscil- 

 lations, whose velocity is aijain found to be 2'3 km. per second. 

 Dr. Cancani remarks that these results agree with the theory 

 explained by him in a former paper {Ann. ilell' Uff. Ccntr. lU 

 Met. e Geod. vol. xv. 1893). 



News has recently been received regarding the three at- 

 tempts made last year to extend our knowledge of the higher 

 mountains of Africa. The most important of these was Mr. 

 Scott Elliot's expedition to Ruwenzori, some of the preliminary 

 results of which he announced in a recent letter to Nature. 

 Mr. Scott Elliot seems to have found the higher slopes of the 

 mountain extremely trying to the native porters. Botanical 

 results of the highest interest may be expected from the work 

 of such an experienced African botanist. .\s Mr. Scott Elliot 

 did not succeed in reaching the highest zone in the mountain, 

 his description of its geology may be incomplete. He has, 

 however, announced one conclusion of the highest importance, 

 viz, the discovery of traces of the existence of glaciers, seven 

 miles below the existing snow-line. It will be remembered 

 that in a recent paper published by the Geological Society, 



; Dr. J. \V. Gregory fully described similar glacial extension on 

 Mount Kenya. The difficulty, however, has heen felt that the 



I same fact has not been recorded from Kilima Njaro, in spite of 

 the numerous visits to thit mountain. The glaciers there now 

 seem to be at their greatest extension. It is probable that 

 this is due to the fact that the peak with the existing glaciers 

 is of very recent date. The absence of moraines from the older 



' peak appeared perplexing. Mr. Scott Ellioi's discovery, how- 



' ever, shows that the greater glaciation of Kenya was not due 

 to a purely local cause, but to some change that affected the 

 whole region. 



We have received a copy of the British Central Africa 

 '/'((■//(• (vol. i. No. 15), describing Capt. Mannin4's recen 

 asunt of Mount Mlanje, on October 22-25. The mountain ist 

 now well known irom the botanical collections made there by 



] Mr. Whyte, under the direction of Mr. H. H. Johnston. Pre- 

 vious attempts to ascend it hid, however, failed through lack 

 of time. Capt. Manning's party do not appear to have found 

 the climbing very difficult. The summit is estimated at 

 9680 feet ; but we are not told by what method this was deter- 

 mined. Apparently it was only by aneroid. The parly were 

 helped up by a new method of roping, which ought to recom- 



I mend itself to the Chamounix and Zermatt guides. They used 



ja long loop of calico, which they called a " machila " : the 

 climber leant back at one end of it, six or eight stiong men 



j pulled at the other. Probably in time, to " machila theMatter- 



I horn " will be the regular thing in a Swiss trip. 



The third expedition to which we have to refer, has unfor- 

 . tunately not been successful in its attempt to solve the mystery 

 of the reported snow-clad mountain which occurs between 

 Kenya and .Vbyssinia. The existence of this has been fre- 

 .^uently reported since it was first recorded by Abbadie as 

 Mount Wosho. It was hoped that Dr. Donaldson Smith's 

 expedition would have finally settled this question of the height 

 and position of this mountain. The expedition has, however, 

 been stopped by the Ahyssinians, and sent back to the Somali 

 frontier at Barri. His companion, Mr. Gillatt, has been com- 

 pelled to return home, but Dr. Smith has determined to con- 

 tinue the expedition. As the rainy season and unhealthy 

 country arc before him, and as such people as the Somali are 

 easily dispirited by a first failure, it is hardly likely that Dr. 

 NO. 1323, VOL. 51] 



.Smith will reach Miunt Wosho. He proposes to strike south 

 for the Juba, and then westward across the Borana country to 

 Basso Narok (Lake Rudolph). The expedition has already 

 achieved some very interesting results, and if it succeed in its 

 traverse of the Borana country, it will have amply atoned for its 

 failure to reach its original goal of the Omo valley. 



In an address to the United States National Geographic 

 Society, recently published in the National Geographic Magazine, 

 Dr. C. Hart Merriam discusses the influence of temperature upon 

 the geographical distribution of terrestrial animals and plants. 

 It is well known that in the northern hemisphere animals and 

 plants are distributed in circurapolar belts or zones, the boundaries 

 of which follow lines of equal temperature ; but difference of 

 opinion prevails as to the period during which temperature 

 exerts its restraining influence. Dr. Merriim opens new ground 

 in the address to which we refer. Physiological botanists have 

 long maintained that the various events in the life of plants, such 

 as leafing, flowering, cS:c. , take place when the plants have been 

 exposed to definite qaantitiesof heat, which are the sums total 

 of the daily temperatures abive a minimum (6° C. ) assumed to 

 tie necessary for function U activity, and are termed the physio- 

 logical constants oi l\\e particular stages. Dr. Merriam infers 

 from this that there must also be a physiological constant for 

 the species itself; and this species constant must be the total 

 quantity of heat required by a given species to complete its 

 cycle of development and reprodacti in. It folljws that not 

 only the mean temperature, bat .also the total quantity of heat 

 in particular zones must be considered in estimating the 

 influence of temperature upon the distribution of plants and 

 animals. Dr. Merriam has constructed a pair of isothermal 

 charts of the United Slates, of which one shows the distribution of 

 the total quantity of heat during the se.ason of growth and 

 reproduction (i.e. the sum of daily mean temperatures above 

 6° C), and the other the mean temperatures during the six 

 hottest weeks of the year. B)r conparing these with a bio- 

 geographical chart of the same region. Dr. Merriraan concludes, 

 from the striking coincidences which occur, that animals and 

 plants are restricted in northward distribution by the total 

 quantity of heat during the season of growth and reproduction, 

 and in sou'hward distribution by the mean temperature of a 

 brief period during the hottest part of the yeir. The anomalous 

 intermingling of boreal ami austral types which occurs over an 

 extensive area of the Pacific coast of the United States becomes 

 explicable by the establishment of these principles, for here 

 alone is a low summer temperature combined with a high sum- 

 total of heat — the two conditions which permit extensive 

 mixture in the same region of northern and southern types. 



A CASE of dual brain action, presenting points of special 

 interest, both in physiology and psychology, is described in 

 '■train (Part Ixix.) by Mr. L. C. Bruce. The patient who 

 formed the subject of observation varied considerably in his 

 mental condition, and the most obvious phenomena observed 

 during these changes were thit in one condition he spoke the 

 English language, and in the other the Welsh language. When 

 in the former state, he was the subject of chronic mania. He 

 was right-handed, and exhibited a fair amount of intelligence. 

 He remembered clearly things he had noticed in previous 

 English periods, but his memory was a blank to any that 

 occurred during the Welsh stages. He wrote by preference 

 with his right hand, his letters were fairly legible, and he wrote 

 from left to right. If asked to do so, he would write with the 

 left hand, but then produced mirror writing, traversing the 

 paper from ri^ht to left. When in the Welsh stage, however, 

 he was left-handed and the subject of dementia. His speech 

 was almost unintelligible, but what could be understood was in 

 the Welsh language. In this stage he had no idea of English,. 



