544 



NATURE 



[April 9, 1^96 



had held its own without migration even to the present time, 

 and that the hypothe.sis of destruction and migration of plants 

 from north to south and back again was unnecessary to account 

 for the actual facts of distribution. 



In connection with M. Ragonneau's reported explanation of 

 the "mango trick" of Indian native conjurers, it may be 

 interesting to compare his results with Moggridge's observations 

 on the harvesting ants of the Riviera. According to M. Ragon- 

 neau, the Indians sow the seed under experinient in earth which 

 has been taken from an ants' nest, and the formic acid present 

 causes it to germinate with extraordinary rapidity, and " grow 

 up into a tree " before the astounded spectator. The French 

 observer states that he has reproduced this experiment in every 

 detail by sowing seeds in earth previously watered with a dilute 

 solution of formic acid. On the other hand, Moggridge found 

 that in seeds stored in the granaries of the Mediterranean ants 

 the process of germination was indefinitely delayed. That their 

 vitality was not destroyed was proved by removing and planting 

 them in fresh earth, when they grew immediately. That ants 

 should be capable of exerting such opposite influences on the 

 growth of seeds is remarkable. 



An interesting investigation on the specific heat of solutions 

 has been given by Herr G. Tammann {Zeitschrift fiir Physikal- 

 ische Chemie). It is well known that weak solutions of certain 

 electrolytes have a smaller capacity for heat than the water pre- 

 sent in them possessed previously to the introduction of the salt, 

 and the object of the investigation is to establish a connection 

 between this phenomenon and the contraction of volume which 

 accompanies the process of solution. This contraction has often 

 been accounted for by the hypothesis of a certain internal mole- 

 cular pressure. Herr Tammann calculates the specific heat of 

 the water present in a number of solutions of this class on the 

 supposition that their pressure is the increased pressure pos- 

 tulated by the above theory, and he also calculates the specific 

 heat of the dissolved substance, that of the mixture being deduced 

 by adding the thermal capacities of the two components. The 

 theoretical values thus obtained are found to agree closely with 

 the values experimentally found by observing the solutions them- 

 selves, and it is inferred that contraction is the sole cause of the 

 diminution of specific heat arising from the presence of the dis- 

 solved matter. 



As an addition to the information about Northern Norway, 

 contained in Dr. Reusch's article in Nature of March 5, we 

 give the following data as to cloudiness, communicated to Mr. 

 Lawrence Rotch by Prof. H. Mohn, Director of the Norwegian 

 Meteorological Institute, and sent by him to Science. Prof. 

 Mohn writes : " For Sydvaranger, the nearest place to Vadso at 

 which meteorological observations have been made, the amount 

 of cloud on a scale of o to 10, and the chance in percentages of 

 its occurrence are as follows : — 



lOO-I lOOI 



Sydvaranger lies on the south side of the Varangerljord, and 

 Elvenes is the name of the posting station. Vardo, lying on 

 the north side, is not to be recommended, having too often fog 

 or clouded sky. In the interior of Finmarken the sun is lower 

 than at Varangerfjord." Although the astronomical conditions 

 NO. 1380, VOL. 53] 



of low altitude of sun and short totality are not good, yet Mr.. 

 Rotch thinks the meteorological conditions just noted compare 

 favourably with those of stations in Japan, where the eclipse 

 occurs later in the day and totality lasts longer. 



From materials collected by the Meteorological Office from 

 merchant ships' logs since the year 1854, from data contained in 

 the logs and Remark Books of the Royal Navy since 1830, and 

 from other sources, the Meteorological Council have prepared 

 monthly current charts for all oceans, which will certainly prove 

 of much value to navigators. The Hydrographic Office of the 

 Admiralty has undertaken to generalise the large amount of 

 material which has been collected, and already the charts for the 

 Indian Ocean have been published. These generalised sheets 

 show the average direction and rate of the currents, and 

 other details ; much valuable information has hitherto been 

 masked by the grouping of the data for longer periods. They 

 show, for instance, that near the African coast there is no month 

 between January and July in which the rate of the Agulhas 

 current does not occasionally reach 100 miles in 24 hours, and 

 also that it follows very different routes after reaching the latitude 

 of the Cape. The currents of the Bay of Bengal are shown to be 

 subject to very abrupt changes with the change of the monsoon, 

 but do not follow the precise direction that might be expected. 

 In January there is a well-marked southerly drift near the coast, 

 while in February the current assumes an entire change of 

 direction, and sets to the northward. Similarly, important 

 changes are shown to exist in the current round the southern 

 part of Ceylon. 



An ingenious and novel method, which it is hoped may prove 

 of service in distinguishing genuine cholera-vibrios from their 

 numerous rivals, has been recently introduced by Prof. Pfeiffer 

 and Dr. Vagedes. Taking advantage of the now recognised 

 fact, that the serum derived from cholera-immunised animals 

 contains anti-cholera substan(;es, Dr. Pfeiffer has traced the 

 effect produced outside the body from cholera-vibrios when 

 brought into intimate contact with such serum in artificial 

 cultures. For this purpose broth, to which highly active cholera- 

 serum was added, was inoculated with cholera-vibrios, and the 

 effect watched under the microscope in hanging-drop cultures. 

 The vibrios, usually so active, were almost immediately deprived 

 of their powers of movement, and after twenty minutes*^ 

 exposure to a higher temperature in the incubator, all traces of 

 motility had vanished, although no morphological difference 

 could be discovered in their appearance. When, however, such 

 drop cultures were allowed to remain for twenty-four hours in 

 the incubator, the vibrios were found to have almost completely 

 regained their old activity, indicating that the original inimical 

 effect produced by the serum had to a great extent been overcome. 

 Dr. Pfeiffer states that this remarkable influence of the cholera- 

 serum was only apparent with true cholera-vibrios, all the other 

 numerous descriptions of allied vibrios which were examined 

 being totally unaffected. Further extensive trials must be made 

 before passing a final opinion upon this new method of cholera 

 diagnosis, and Dr. Pfeiffer has expressed his willingness to assist 

 all such investigations by supplying cholera-serum of the 

 requisite degree of strength, to those who desire to carry out 

 similar experiments. 



A SHORT paper by Mr. H. W. Seton-Karr, on his discovery 

 of evidences of the palseolithic stone age in Somaliland, appears- 

 in the latest number of the journal of the Anthropological 

 Institute (vol. xxv. No. 3, 1896). His observations show that 

 stone implements in Somaliland are found scattered all over the 

 country, but probably mostly below the present surface, within 

 a district included roughly between the Red Sea and lat. 9° 30' N. , 

 and between E. long. 44° and 45°. Dr. Gregory made a col- 

 lection of obsidian implements in Masai-land, but these were all 

 neolithic ; and he points out that, as no palaeolithic implements 



