92 



NA TURE 



[May 25, 1905 



motion from Edinburgh, Paisley, Beirut, and Toronto. — 

 Charts of the Gulf of St. Lawrence, showing the co-tidal 

 lines at mean time of Quebec : Captain Tizard, C.B., 

 F.R.S. — Photographs of the " Cullinan " diamond : Sir 

 William Crookes, F.R.S. 



Microscopic preparations illustrating the development of 

 calcareous spicules in various invertebrate animals : Prof. 

 E. A. Minchin and Mr. W. Woodland. Calcareous 

 spicules are small skeletal elements to be found in most 

 of the lower animals. These spicules assume varied and 

 often beautiful forms, those of sponges and " sea 

 cucumbers " (Cucumariida; and Synaptidce) being especially 

 striking in this latter respect, and are built up in all 

 instances by the agency of scleroblasts — small nucleated 

 protoplasmic masses which deposit the lime. The causes 

 underlying the production of the curious forms which these 

 spicules assume (triradiates, perforated plates, wheels and 

 anchors, &c.) are not by any means yet understood, but 

 are probably several in number, some being purely 

 mechanical in nature, others, perhaps, being those which 

 give rise to crystals. — Cellular constituents peculiar to 

 cancerous and reproductive tissues : Prof. J. B. Farmer, 

 F.R.S., Mr. J. E. S. Moore, and Mr. C. E. Walker. In 

 the cells of malignant tumours, structures known as 

 *' Plimmer's bodies " are present in most cases. These 

 structures have been regarded as parasitic organisms or 

 as specific cellular peculiarities confined to such malignant 

 tissues. They have recently been identified as also being 

 present in normal reproductive tissues. Thev form a 

 definite organ of the cell during its conversion to a sper- 

 matozoon, and they also can be identified in the two pre- 

 ceding divisions. They are absent from other cells of the 

 body. — The simplest kind of protoplasm : Dr. Charlton 

 Bastian, F.R.S. One drop of a fluid swarming with 

 common bacteria had been introduced into one ounce of 

 distilled water containing ten grains of neutral ammonic 

 tartrate in solution. The bacteria grow freely in this 

 fluid, and as the constitution of the ammonia salt is 

 2NH4O, C,H^O,„-|-2HO, they must fashion their proto- 

 plasm in some way from C, H, O, and N only, though 

 sulphur and phosphorus, one or both, are commonly re- 

 garded as necessary constituents of living matter. 



The parasite of " kala azar " : Brevet Lieut. -Colonel 

 W. B. Leishman. This protozoal organism is found in 

 the spleen and other organs in cases of " kala azar," an 

 extremely fatal disease occurring in epidemic form in 

 Assam, and also, in endemic form, in other parts of India 

 and the tropics. Nothing is yet known as to the mode of 

 infection or as to the life of the parasite outside its human 

 host. In artificial cultures it develops into a flagellated 

 organism closely resembling a trypanosome. Specimens 

 and sketches were shown of the parasites as they occur 

 in the tissues, and of the flagellated forms into which 

 they develop in artificial cultures. — The isolation of B. 

 typhosus from water by means of alum precipitation : Mr. 

 H. S. Willson. Alum is added to the infected water in 

 the proportion of 05 gram to the litre. When the pre- 

 cipitate of aluminium hydrate has fully formed, the water 

 is centrifugalised and the sediment containing most of the 

 bacteria present in the water is spread on plates of suit- 

 able media, and incubated at 42° C. The precipitate, 

 which is known to be destructive to many water and 

 sewage organisms, has no germicidal action on B. 

 typhosus. 



(i) Stone adze heads in various stages of manufacture, and 

 chips from the neighbourhood of Suloga, Woodlark Island, 

 British New Guinea ; (2) photographs of straight-haired in- 

 dividuals from Nara district central division, British New 

 Guinea ; (3) wood carvings and drawings, principally from 

 Massim district, British New Guinea : Mr. C. G. Selig- 

 mann. Specimens of cross-bred maize illustrating inheritance 

 in accordance with Mendel's law : Mr. R. H. Lock. — Living 

 representatives of the Plymouth marine fauna : Marine 

 Biological Association. Material obtained with the dredge 

 from certain typical grounds in the neighbourhood of 

 Plymouth was shown, together with representatives of the 

 animals living on each ground. — Photographs illustrating 

 young cuckoo in the act of ejecting egg and young bird 

 from nest of foster-parent : Mr. W. Percival Westell. 



A new problem on superposition : Mr. H. E. Dudeney. 

 This was a demonstration that an equilateral triangle can 



NO. 1856, VOL. 72] 



be cut into four pieces that may be re-assembled to form 

 a square, with some examples of a general method for 

 transforming all rectilinear triangles into squares by dis- 

 section. 



Oil painting, a Friday evening lecture at the Royal 

 Institution : Mr. H. J. Brooks. 



ATMOSPHERIC ELECTRICITY OBSERVED 



FROM BALLOONS. 

 T T is now some years since attempts were first made to 

 investigate the electrical conditions of the upper atmo- 

 sphere by aid of manned balloons ; but it is only within the 

 last three years that the difficulties of the observations and 

 the proper methods to be used have been anything like 

 understood. 



Measurements of the normal potential gradient were 

 first attempted. The early observers worked very much 

 in the dark, Linke being the first, in 1901, to investigate 

 the errors due to the mere presence of the balloon itself. 

 He found that for the influence of an uncharged balloon 

 to be small enough to be neglected, the upper of the two 

 collectors used must be at least 10 metres below the basket. 



Linke also investigated the efficiency of different forms 

 of collectors. The original form of collector used in 

 balloon work was a modification of Kelvin's drop collector. 

 A wire was lowered from an insulated vessel out of. which 

 water flowed and ran down the wire ; the drops forming 

 on the end of the w-ire and then falling off brought the 

 whole wire to the potential of the air at its end. There 

 are many objections to this form of collector ; it is very 

 slow in action, uses a large quantity of water, and will 

 not work when the temperature falls below freezing. 

 Flame collectors are obviously out of the question for 

 balloon work on account of their danger, and, much to the 

 regret of the experimenters, radium did not come up to 

 expectation. The difficulty w'ith radium collectors is that 

 the radium ionises a large volume of air, which, on account 

 of the absence of relative motion between the balloon and 

 the surrounding air, travels along with the balloon and 

 completely alters the electrical conditions of the atmosphere 

 in its neighbourhood. By a simple device Linke has 

 finally overcome all difficulties connected with the col- 

 lectors. A vessel containing spirits is insulated on a 

 shelf fastened to the outside of the basket. From this 

 vessel hangs a long thin lead or other flexible pipe. At 

 the lower end of the pipe is a nozzle which forms the 

 collector proper. As stated above, the collector must be 

 10 metres below the balloon ; thus there is at least a 

 lo-metre head of liquid acting at the nozzle. The pressure 

 due to this causes a very fine jet to escape from a pin- 

 hole in the nozzle. As the jet breaks up into exceedingly 

 fine drops, a very rapid collector action takes place. Col- 

 lectors of this form have acted splendidly, and their use 

 makes it possible to measure the potential gradient with 

 accuracy and ease. 



The rate of dissipation of electricity from a charged 

 body, and the degree of ionisation of the air, have also 

 been made subjects for investigation in the upper atmo- 

 sphere. Ebert and Linke have devoted several ascents to 

 measurements of the dissipation, and Ebert designed the 

 first instrument to measure the natural ionisation of the 

 air ; but the ionisation has been most carefully investigated 

 by Gerdien, who improved Ebert's instrument so that it 

 measures not only the ionisation, but the conductivity of 

 the air also. 



It was when making these latter investigations that a 

 number of difficulties connected with the casting of ballast 

 were first observed. Ebert found that the pouring of sand 

 from the ballast bags so highly charged the balloon with 

 friction electricity that electrical observations became im- 

 possible. Gerdien found that after sand had been cast 

 the balloon remained for some minutes in an atmosphere 

 filled with fine sand dust, which greatly affected the 

 measurements of the ionisation. Linke also found that on 

 account of the sudden upward acceleration given to the 

 balloon after sand had been cast the position of the electro- 

 scope leaves changed without any change of voltage. 

 Gerdien was the first to overcome these difficulties. 

 Besides sand, he took two large watertight sacks filled 



