4i8 



NA TURh 



[June 2, 1910 



students has more than doubled during this period, the gain 

 being one of 113 per cent., that is, from 27,424 to 58,342. 

 There has been a marked change, too, in the relative 

 position of the various German universities since 1893-4, 

 when the largest universities were, in order, Berlin, 

 Munich, Leipzig, Halle, Wurzburg, Bonn, and Breslau. 

 The only university that shows a decrease in the attendance 

 of matriculated students as against 1894 is Wurzburg, and 

 there the loss is very slight. 



SOCIETIES AND ACADEMIES. 

 London. 

 Royal Society, May q.— Mr. A. B. Kempe. treasurer ano 

 vice-president, in the chair.— Colonel Sir David Bruce, 

 Captains A. E. Hamerton and H. R. Bateman, and 

 Captain F. P. Mackie : The development of trypanosomes 

 in tsetse-flies. Until the end of 1908 it was believed that 

 tsetse-flies acted merely as mechanical agents in the trans- 

 ference of trypanosome diseases. The parasite was sup- 

 posed to be carried by the fly in the same way that vaccine 

 lymph is carried— on the point of a lancet from one child's 

 arm to another. The limit of time of infectivity of the 

 fly vvas placed at forty-eight hours, and it was believed 

 that if an infected area were emptied of its sleeping-sick- 

 ness inhabitants for a couple of days, it would then be 

 quite safe for healthy persons to enter it. At the end of 

 1908 Kleine made the discovery that a tsetse-fly could 

 convey a trypanosome for some fifty days after the fly 

 had fed on an infected animal. The experiments were 

 carried out on these lines in Uganda. Both lake-shore 

 and laboratory-bred flies (Glossina palpalis) were used, and 

 various trypanosome diseases besides sleeping sickness were 

 experimented with. Tsetse-flies are numerous on the lake- 

 shore, 500 or more being caught every day by a few fly- 

 boys. The flies brought up from the lake-shore were 

 found to be naturally infected with at least two species of 

 pathogenic trypanosomes, so that it was afterwards found 

 necessary to use flies bred in the laboratory from pupas 

 gathered on the lake-shore. At first it was difficult to 

 find these pupa?, but after some time the supply was more 

 than sufficient, as many as 7000 being brought up in one 

 day by a few natives. These experiments go to show that 

 a iate development of trypanosomes takes place in about 

 5 per cent, of the flies used. This development of trypano- 

 somes in the inside of a fly renders the fly infective and 

 capable of giving the disease to the anima'ls it feeds on. 

 The shortest time which elapsed before a fly became 

 infective after feeding on an animal infected with sleeping 

 sickness was eighteen days, the longest fifty-three days, 

 and the average thirty-four days. An infected fly has been 

 kept alive in the laboratory for seventv-five days, and re- 

 mained infective during that time. It" is not known how 

 long the tsetse-fly may live under natural conditions on the 

 lake-shore. Experiments made to test directly the dura- 

 tion^ of the infectivity of tsetse-flies show that they can 

 retain their infectivity for at least two years after the 

 native population has been removed from "the fly area. — 

 Dr. H. G. Cliapman : The weight of precipitate obtain- 

 able in precipitin interactions. — Miss Ida F. Homfray : 

 The absorption of gases by charcoal. The experimental 

 portion of the work here summarised consisted in deter- 

 mining the volumes of gas absorbed by a known weight 

 of charcoal,^ 3 grams, at definite temperatures, varying from 

 that of liquid air to that of boiling aniline, and at pressures 

 up to 80 cm. of mercury. The gases used were He, A, 

 N,, CO, CH|, C„H,, CO2, Oj, and mixtures of N, and 

 CO. After making all necessary corrections, the" iso- 

 thermals were constructed, and from them points of equal 

 absorption were read off, the family of curves so obtained 

 being termed the isosteric diagram. The concentration for 

 each isostere was calculated in the form 



C = 



W + w' 



where w is the weight of gas absorbed and W that of the 

 gas-free charcoal. The concentration of pure gas when 

 W = o thus becomes 100 per cent. Two relations have been 

 obtained which hold, within experimental accuracy, for all 



NO. 2 1 18, VOL. 83] 



these gases : — (i) each isostere follows Ramsay and 

 Young's rule f«r saturated vapours, 



^O-^^^RCTo-T'o), 

 'i * 1 



and is expressible by Bertrand's vapour-pressure formula,' 

 (2) at constant pressure rfT/dlogC = K. Also, in all casesi 

 at low pressures, and in some cases at all pressures, when] 

 these straight lines are produced to logC = 2, i.e. 100 per 

 cent., the corresponding temperature is found to be the 

 recognised boiling point of the liquefied gas at that pressure. 

 By means of a simple formula the heats of absorption at; 

 various concentrations were calculated, and the thermo- 

 dynamical relations are comparable to those of concen- 

 trated solutions. Calorimetric measurements were made in 

 the case of CO,, and found to agree well with the calcu- 

 lated values. The suggestion put forward, as a result of 

 the experimental work, is that a homogeneous solution 

 phase is formed in equilibrium with the gas phase, the 

 presence of a large concentration of charcoal greatly 

 raising the equilibrium temperature of the volatile com- 

 ponent at a given pressure. This rise is not constant, aa 

 in the case of dilute solutions, but is itself inversely pro- 

 portional to the gas concentration. If any other function 

 of the quantity of charcoal, such as its surface area, were 

 substituted for the mass in calculafing the concentration?, 

 the relations between the absorption results and the con- 

 stants for the liquefied gases would be lost. For mixtures 

 of two gases in charcoal the phase rule holds, and tl 

 relations can be deduced from those of the components. 



Royal Meteorological Society, Mav 25. — Mr. I! 

 Mellish, president, in the chair. — W. C. Nash : The 



daily rainfall at the Royal Observatory, Greenwich, 

 1841-1903. From the statistics given in this paper it 

 was shown that the average annual rainfall for the sixty- 

 three years was 24' 19 inches with 157 rain days. The day 

 with the maximum number of rain days to its credit is 

 December 5, while the days with the least number of 

 rain days are April 18, 19, June 27, and September 13. 

 There were ninety-four occasions during the whole period 

 on which the rainfall exceeded i inch in the day. The 

 greatest fall was 3-67 inches, on July 26, 1867. — L. C. W. 

 Bonacina : Low-temperature periods during the winters 

 1908-9 and 1909-10. It is often observed that if a given 

 week, month, or other period in one year is marked by 

 some very special meteorological character with respect to 

 one or more elements of weather, the corresponding period 

 the following year shows exactly the opposite character. 

 Dealing with the last two winters, the author directed 

 attention to four very remarkable frosts which stand out 

 prominently, viz. : — (i) December, 1908, in the south of 

 England ; (2) March, 1909, in the south of England ; (3) 

 November, 1909, in Scotland and Ireland ; and (4) January, 

 1910, in Scotland and the north of England. — R. Corless : 

 The rate of rainfall at Kew in 1908. A method was 

 described of obtaining information about the rate of fall of 

 rain from the records of a self-recording rain-gauge, which 

 yields a continuous trace showing, by the position of the 

 pen, the amount of rain fallen. 



P.ARIS. 



Academy of Sciences, M^y 25. — M. Emile Picard in the 

 chair. — Remajks by the president on the forthcoming meet- 

 ing of the International Association of Academies at 

 Rome. — H. Deslandres : The influence of comets on the 

 terrestrial atmosphere according to the kathodic theory. 

 The study of Morehouse's comet showed that the whole 

 of the light emitted by the tail was of kathodic origin, 

 and it is highly probable that the tails of comets emii 

 penetrating rays analogous to the 7 rays of radium. Thes« 

 rays could ionise the atmosphere and cause the immediato 

 condensation of supersaturated water vapour. Hence ■. 

 connection is at least possible on this theory betwe 

 Halley's comet and the weather. — P. Villard and 

 Abraham : The existence of two explosive potentials 

 For a given system of electrodes two explosive potential 

 exist. The first is the potential of the brush discharge 

 the second appears to be the normal explosive potential 

 and is more definite. Between these two limits there is i 

 continuous silent discharge. — A. Haller and A. Comtessei 



