Sept. 4, 1884] 



NA TURE 



457 



might indeed almost conclude that the masses of the comets 

 arc inappreciable. Let us briefly indicate the grounds for this 

 important conclusion. 



The sun and the planets form a system characterised by perfect 

 order and symmetry. We have the sun in the centre. We have 

 all the great planets moving round the sun in the same direction. 

 They all move nearly in circles, and all these circles lie nearly in 

 the same plane. This organisation is a necessary modus vivenili 

 among the bodies of our system. Each planet acts and reacts 

 upon all the other planets, but, owing to the circumstances of 

 their movements, their irregularities are but small, and the per- 

 manence of the system is insured. Alter that system to any 

 extent, merely reverse for example the direction in which one of 

 the planets is moving, and the whole compromise is destroyed. The 

 actions and reactions, instead of being quickly balanced, will go 

 on accumulating, and the seeds of confusion and ultimate disso- 

 lution have been sown. But we have in our system thousands 

 of comets which repudiate all the regulations by which the 

 planetary convention is restrained. Comets come in what 

 direction they please, they move in every plane but the right one, 

 and their orbits are not in the least like circles. The very fact 

 that our earth continues to revolve around the sun so as to be a 

 fit abode for life, is a proof that comets cannot have any con- 

 siderable mass. If comets had mass then organic disease would 

 be introduced into the solar system which must ultimately prove 

 fatal. 



Science has gradually dissipated the fears which once invested 

 comets : they are interesting and beautiful visitors whichcome to 

 please and to instruct, never to threaten or to destroy. 



NOTES 

 The autumn Congress of the Sanitary Institute of Great 

 Britain will be held this year at Dublin, and the programme of 

 the proceedings has been issued. The President of the Congress 

 is Sir Robert Rawlinson, C.B., who will open the Congress with 

 an inaugural address on Tuesday the 30th inst., and the proceed- 

 ings will last until October 4. The Congress is divided into 

 three sections — the first, "Sanitary Science and Preventive 

 Medicine" ; the second, "Engineering and Architecture" ; and 

 the third, " Chemistry, Meteorology, and Geology." Of the 

 first section, the president is the Registrar-General for Ireland, 

 Mr. Thomas W. Grimshaw, M.A., M.D. In the section of 

 " Engineering and Architecture," the president is the Engineer- 

 ing Inspector of the Local Government Board for Ireland, Mr. 

 C. D. Cotton, C.E. ; and the president of the section of " Che- 

 mistry, Meteorology, and Geology " is Mr. C. A. Cameron, 

 M.D., the City Analyst and Superintendent Medical Officer of 

 Health for Dublin. The sectional meetings and the general 

 meetings will be held at Trinity College, where the opening 

 address will be delivered on Tuesday evening by Sir Robert 

 Rawlinson. On Wednesday morning the actual work of the 

 Congress will commence with the address of the president of the 

 first section, and the remainder of the day will be taken up with 

 the reading of papers and their discussion, while a conversazione 

 will be held in the evening. The business of the second section 

 will be taken on Thursday, October 2, and in the evening a 

 lecture will be delivered to the Congress by Dr. Alfred Carpenter 

 nn "Education by Proverb in Sanitary Work." On Friday, 

 after the third section, the closing general meeting of the Con- 

 gress will be held. Arrangements for excursions will be made 

 for the Saturday. 



The fifth International Congress of Hygiene, which has con- 

 cluded its session at the Hague, is reported to have been highly 

 successful ; it was decided to accept the invitation from Vienna 

 for 1886. 



It is reported that Mr. Melville, chief engineer of the Jeannette 

 Expedition, will command a Polar expedition which it is said 

 will start next autumn to attempt to reach the Pole via Franz 

 Josef Land. It is stated that Mr. Cyrus Field and the New York 

 Yacht Club will each furnish one-half the cost of the expedition. 



In the course of the present month a geographical professor- 

 ship will be established at each of the Russian universities. In 

 Germany, fourteen out of twenty-one universities have a chair 

 of this sort. 



A very favourable Report has been issued of the second year 

 of the College Hall of Residence for Women Students. That 

 such an institution was wanted is shown by the fact that last 

 autumn another house had to be added in order to meet the 

 number of applications from students. The Hall is already 

 almost self-supporting, and in another year will probably be 

 entirely so ; and it is hoped that this will encourage friends to 

 assist the Committee in paying off the 1000?. they had to borrow 

 in order to extend the premises. Subscriptions and donations 

 may be sent to Mrs. Edward H. Busk, 44, Gordon Square, W. C. 



The Geographical Society have received a letter from Mr. 

 H. II. Johnston, who has been sent out to explore and collect 

 plants on Mount Kilimanjaro. It is dated June 18, from " Uvura, 

 in Chagga, altitude 5000 feet." " For nearly a week now,' 

 Mr. Johnston says, "I have been settled on Kilimanjaro, camped 

 on one of the loveliest sites in the world. Above me towers 

 into the deep blue heaven the snowy head of Kibo, around me 

 are green hills and forest-clad ravines in whose profound depths 

 great cascades of water leap from rock to rock and splash the 

 fronds of luxuriant ferns ; before me lies spread out a vast blue 

 plain — 'all the world,' as my host, the chief Mandara, proudly 

 says, and my view southward is only bounded by the distant 

 horizon. Perched as I am up here on the shoulder of a great 

 buttress of the mountain, I seem to be on a level with the upper- 

 most flight of the vultures, who hardly ever soar higher, and 

 who poise themselves and wheel in circles over the awful depths 

 at my feet. When the first cares of my installation are over, I 

 am going to set to work on a picture such as I see before me, 

 and call the view ' a vol de vautour.' " 



The difference between the temperatures of places in Ame- 

 rica and those of places in similar latitudes in Europe is already 

 well known, but it would hardly be expected to be so great as 

 it actually was in January of this year. That month was a 

 mild one all over Europe, but in the United States, especially 

 in the eastern part, it was extremely cold. Thus, in Nashville 

 and Knoxville, in the same latitude as Malta, the thermometer 

 marked 26°7 C. and 23°'3 C. of cold, while in Malta it was 

 only 5°'9 below zero. At Indianapolis and Columbus it was 

 3i°7 C. and 28°'9 C. respectively below zero, while at Madrid, 

 in the same latitude, the maximum was 9 below zero. The 

 average temperature of the month in the States was 3° C. to 

 5° C. beyond the normal average. 



The experiment of MM. Renard and Krebs in balloon 

 steering at Meudon, of which so much has recently been heard, 

 formed the subject of a paper read before the Academy of 

 Sciences on the iSth ultimo. The solution of the problem of 

 aerial navigation was first attempted in 1855 by M. Giffard, who 

 employed steam, then in 1S72 by M. de Lome, and finally by 

 M. Tissandier, who was the first to apply electricity. The 

 conditions which MM. Renard and Krebs studied to fulfil were 

 steadiness of the path obtained by the shape of the balloon, and 

 the arrangement of the rudder ; the diminution of resistance 

 while travelling by the proportion of the dimensions — bringing 

 together the centres of traction and resistance ; and finally, to- 

 attain a speed capable of resisting the winds prevailing in France 

 during the greater part of the year. The paper then enters into- 

 details of the construction, and of the journey, during which the 

 writers claim they were able to manoeuvre the balloon as easily 

 and effectively as a ship is put through its evolutions. 



We have recently received from various scientific societies in 

 the United States their late publications. The contents of the-. 



