June 25, 1903] 



NATURE 



181 



fall since the beginning- of the year is in excess of the 

 average in all districts, varying from more than lo inches 

 in the north of Scotland to 09 inch in the north-east of 

 England. During the first three weeks of this month the 

 amount measured near London was upwards of 6 inches; 

 the Greenwich records for the last 60 years show that the 

 heaviest previous fall in June was 5.80 inches, in the year 

 i860. At Malin Head the fall in the sarn^ three weeks was 

 only 005 inch, and at Holyhead only 04 inch. But on 

 June 22 an area of low barometric pressure reached our 

 western coasts and occasioned heavy rain, amounting to 

 an inch and three quarters at Valencia in the forty-eight 

 hours ending 8h. a.m. on June 24. 



The cleanliness of electric lighting has always been urged 

 as one of the great claims in its favour, and it has been 

 justly pointed out that the saving effected in redecoration 

 partly balances its extra cost. Although this is true, 

 electric light cannot be regarded as perfectly clean ; it has 

 long been noticed that there is a marked tendency for dust 

 to accumulate on electric light fittings and wires, and on 

 the walls and ceilings in their immediate neighbourhood. 

 This is partly, no doubt, due to the air currents produced 

 by the local heating, but it is also partly an electrical 

 phenomenon. The dust particles floating in the air are 

 presumably at air potential, and are consequently attracted 

 to the conductors on the non-earthed side of an earthed 

 system ; they either stick to these permanently, or remain 

 on them until charged, when they are projected on to and 

 stick to the walls. The defect has naturally become more 

 marked with the increased use of 200-volt systems. If 

 switches are always put, as they should be, in the non- 

 earthed wire, the deposition of dust will only occur during 

 ihe time the lamps are alight, and will be minimised. Mr. 

 n. S. Munro, writing in the Electrical Review, points out 

 that a still further improvement can be effected by using 

 concentric flexible conductors instead of the ordinary twisted 

 cord, the outer conductor being connected to the earthed 

 side of the system. 



Dr. Edington read a paper at the recent meeting of the 

 South African Science Association upon the occurrence of 

 an epidemic among domesticated animals in Mauritius, in 

 which trypanosomata were found in the blood. It attacked 

 rattle, mules, horses, and donkeys, among which it caused 

 an alarming mortality, and seemed to be allied either to 

 nagana or to surra. 



The commemoration day proceedings of the Livingstone 

 ( ollege were held at Leyton on June 10. The College 

 trains missionaries in the elements of medicine and surgery. 

 The Bishop of St. Albans, who presided, stated that there 

 lould be little doubt that the average life of a man abroad 

 was considerably extended when due care was taken to 

 observe the rules of health. He referred to the importance 

 of training women as medical missionaries for work in 

 India, and to the moral eff'ect exerted upon native races 

 by curing their bodily ailments. 



The annual return showing the number of experiments 

 performed on living animals in the United Kingdom during 

 1902 has been issued as a Parliamentary paper (186). In 

 England and Scotland the number of licensees was 319, of 

 whom 112 performed no experiments. The total number 

 of experiments performed by these was 14,906, of which 

 2130 were carried out under anaesthetics, and the remainder, 

 '2,776, were of the nature of hypodermic inoculations. The 

 inspector, in his report, directs attention to the large 

 number of experiments performed for the preparation of 

 remedies and on behalf of various public authorities. Five 

 NO. 1756, VOL. 68] 



licensees alone performed 3857 inoculation experiments for 

 testing anti-toxins, and fifteen licensees 3997 inoculations 

 for public bodies for the purpose of testing milk for tubercu- 

 losis, for the examination of sewage and of air, and the 

 like. As regards Ireland, 13 licences were in existence 

 during the year, and 65 experiments were performed under 

 them. 



We have received from the director of the Survey Depart- 

 ment, Cairo, a report on the meteorological observations 

 made at the Abbassia Observatory during the year 1900, 

 together with mean values for Alexandria for the previous 

 ten years • also monthly results for Port Said, Assiut and 

 Omdurman for part of the year 1900. The report is a 

 very valuable contribution to Egyptian climatology, and 

 bears evidence of every care having been taken in the 

 selection of trustworthy instruments and in the reduction of 

 the observations. The observatory is now well supplied 

 with automatically registering instruments of the best 

 patterns, including Dines 's anemometer, Callendar's electric 

 recorders for dry- and wet-bulb platinum wire thermo-' 

 meters, Campbell-Stokes's sunshine recorder, and Milne's 

 seismometer. For Abbassia hourly observations are given, 

 and the results, with daily and annual variations and other 

 data, are shown in clearly drawn diagrams, both for this 

 station and for Alexandria. From the latter ten-year series 

 we note that the mean of the highest temperatures recorded 

 in each month was 36°-6 C. in May, and of the lowest 

 maxima 2i°-6 in January; the mean of the highest minima 

 was 22°-7 in August, and of the lowest 7°o in January. 

 The extreme values were 40° and 5°-4. The mean annual 

 rainfall is only 953 inches ; most of this falls between 

 November and January. No measurable quantity falls in 

 June, July and August, and only three-tenths of an inch, on 

 the average, in September. 



In our recent notice of Messrs. Burroughs Wellcome and 

 Co.'s " tabloid " preparations for photographers, we re- 

 marked that, among a very large assortment of reagents 

 and mixtures, mercuric chloride and ferrous oxalate 

 appeared to have been overlooked. The firm informs us that 

 the mercuric iodide and sodium sulphite intensifier is so 

 efficient that it does not consider the issue of mercuric 

 chloride tabloids as desirable. We would point out that 

 intensification is the only process subjected to such a limit- 

 ation, and that, although the iodide of mercury method is 

 easily applied and the tabloids are excellent for the purpose, 

 there is no method of intensification that is so simple in 

 its chemical and physical effects, and so trustworthy as to 

 the amount of change produced and the permanency of the 

 resulting negative, as the use of mercuric chloride followed 

 by ferrous oxalate. The same advantages that we have 

 indicated in connection with photographic " tabloids " 

 apply also to the same firm's " ' soloid * microscopic stains." 

 A dozen or more varieties are already issued, the most 

 recent addition being Leishman's modification of Roman- 

 owsky's stain for blood films. Microscopists will appreciate 

 not only the convenience of being able to prepare staining 

 solutions without having to weigh the solid substances, but 

 also the fact that these preparations are made from materials 

 specially selected for the purpose. 



In Science for May 29, Mr. C. A. Chant discusses certain 

 questions connected with theories of colour vision, and in 

 particular a view put forward by Dr. Kirschmann accord- 

 ing to which colour sensation may not be due to the effect 

 of rays of one particular wave-length, but rather to the 

 superposition of rays of different lengths the combination of 

 which produces the effect of colour. That the theory in 

 question is a possible one arises from the fact that " nobody 



