NA TURE 



Ijan. 7, 1 1 



south end of tlie Isle of Man from a depth of about 20 fathoms. 

 It is about I '5 cm. in length, and differs somewhat in shape from 

 both Chtitoda-tna inlidiiliiiii, Loven, and the new species (C. 

 mitilare, Selenka) f jund during the ClialUnger E.xpedition. The 

 calcareous spicules are also different from those of both the pre- 

 viously described species, but they seem to vary considerably in 

 shape. The specimen — along with the other Vermes obtained 

 during the various dredging expeditions carried on last summer 

 by the members of the Liverpool Marine Biology Committee — 

 has been placed in the hands of Mr. R. J. Harvey Gibson, M. A., 

 for detailed examination, and will be described in the First 

 Report upon the Fauna of Liverpool Bay, to be published 

 shoitly. W. A. Herdman 



University College, Liverpool, December 30, 1885 



A Solar Halo 



At about noon on tliis day a fine halo with its mock suns was 

 well seen at the Radcliffe Observatory. Measurements of the 

 vertical radii of the first circle gave 22° 24', whilst the angular 

 distance between the true and mock suns was 22° 30'. The 

 radius of the second circle was rather difficult to determine, but 

 the mean of several measures gave 46° 40'. The inverted arcs 

 at the vertices of the two circles were clearly seen. The zenith 

 distance of the sun's centre was nearly 75° at the time of the 

 observation. E. J. Stone, 



Radclilte Observer 



Radclifte Observatory, Oxford, December 30, 1SS5 



Ventilation 



Mr. Fletcher's letter in your issue of December 17 (p. 153) 

 illustrates the difficulties encountered by people who adopt 

 patent ventilators and so-called systems of ventilation without 

 considering the natural laws ruling the flow of currents of air. 



The exit-shafts recommended by the writer of your article on 

 the subject, as he himself confesses, may act as inlets, and 

 generally do, if theie is no other free inlet for air. This there 

 seldom is in cold weather when the windows are closed, unless 

 a hot-air grate on the Galton or other model is adopted. There 

 is very little objection to running the exit-tube from the chandelier 

 into the chimney fiue, on the same principle as that of the 

 chimney to each ventilator, now so much used. 



I think the writer of your article hardly appreciates the diffi- 

 culties to be encountered in ventilating an English house or 

 assembly-room. Irrespective of the ignorance of the public 

 generally on the subject, we are met by the fact that in most 

 town houses it is very difficult to place a stove, with proper 

 fresh-air inlet, in the entrance, where it may afford a supply of 

 fresh warmed air to the house. As a rule the nearest flue is a 

 very long way off. Again, fire-places being as a rule on inside 

 walls in such houses, the flue to supply a hot-air grate (by far 

 the best method of warming) has to be very long, and there is 

 difficulty in arranging for its due cleansing. 



Your correspondent speaks of expense being no object in the 

 erection of public buildings, This is far from my experience. 

 In the cases of churches, schools, and assembly-rooms, the ques- 

 tion of ventilation is entirely bound up with that of heating, and in 

 conversation with various makers of heating apparatus I have 

 found their views quite unanimous on the peculiarities of 

 building Committees on this subject. The lowest tender is as a 

 rule accepted, and this never provides for ventilation. They are 

 asked to heat only. 



The real objection to ventilation in large rooms is the cost of 

 the necesary heating apparatus. For instance, a large concert- 

 room has recently been erected in this neighbourhood to seat 

 3800 persons, with a cubical content of 514,800 feet. 



Now to warm this in the ordinary manner by hot-water pipes 

 would require about 2600 feet of four-inch piping. But to 

 supply a thousand feet of air per head, heated from 30" to 60° 

 Fahr. would, according to the formula given in Hood's work, 

 require no less than 10,600 feet, or more than four times the 

 amount, while the space occupied by more than two miles of 

 large piping would have to be taken into consideration. 



No doubt the heating could be done more economically by 

 steam coils or large stoves if care be taken not to over-heat the 

 air. 



Until ventilation is considered as necessary as drainage, and is 

 paid for accordingly, and till failure on the part of architect and 

 builder to secure it is visited with as severe penalties as failure 



in points of construction or design, I see no chance of improve- 

 ment on the present state of chaos. Ernest H. Jacob 

 Leeds, December 22, 1SS5 



Travellers' Snake- Stories 



Travellers' "stories " are not expected to be quite matter- 

 of-fact. One of the best of these jokes occurs in an article 

 on " Travellers' Snake-Stories " in the December number of 

 Good Words. Among the natural enemies of snakes the mon- 

 grose is thus described : — 



" The mongoose, a bird known as the kingfisher of Australia, 

 and secretary-bird of Africa, is well known in some of the West 

 Indian Islands almost always to come oft" victorious in its 

 encounters with the rattlesnake, and it has even been proposed 

 to breed it specially for its extirpation." 



From the use of the singular number in the above extract it is 

 clear that only one anim.al is intended to be described, and that 

 one is a bird. Next follows an interesting deicription in con- 

 siderable detail (quoted from the .S'/aWrtrij' of January 22, 1883), 

 of fights between the Indian mongoose and the Indian cobra in 

 Lucknow, ending with the sentence : — 



" He adds that these birds make affectionate pets," S;z, 



This is the best joke of all. It may be that the Australian 

 kingfisher and African secietary-bird are locally called "mon- 

 goose " (this is not within the present writer's experience), but 

 the Indian mongoo-e is a small animal, in shape very like a 

 weasel or a ferret. It is impossible that the writer in the 

 S/iinditrd (who is stated to have himself arranged the mongoose 

 and cobra duels) could have de cribed the mongoose as a dird. 

 What does the man mean ? Allan Cunningham 



Blackbird with White Feather 



I notice a letter from Mr. Murphy in your issue of December 

 24, 18S5, about a blackbird with a white feather in its tail. 

 Allow me to say that last month I saw a cock blackbird with a 

 pure white tail ; the rest of its plumage was natural. I saw it very 

 distinctly, as it was flying away from me at the time, not more 

 than ten yards off when I first noticed it, with its tail extended ; 

 I saw it again last week, within a few feet of the same place, 

 this time running under a gate. My wife says she saw a similar 

 bird, at the same spot, about a year ago. 



Thomas J. Busk 



Ford's Grove, Winchmore Hill, January 4 



It may interest your correspondent, Mr. J. J. Murphy, to 

 know that for the last two years we have had a cock blackbird 

 about our garden with a patch of pure white on each side of the 

 head. E. Brown 



Further Barton, Cirencester, Januaiy 3 



During the frost of January 1880 I frequently noticed a hen 

 blackbird with several white feathers on the head, breast, and 

 back. It was quite tame, and came for food every day. 



Hartford, Cheshire, December 30, 1S85 E. K. 



ON THE METHOD OF RECIPROCANTS AS 

 CONTAINING AN EXHAUSTIVE THEORY 

 OF THE SINGULARITIES OF CURVES^ 

 T T is now two years and seven days since a message 

 -*• by the Atlantic cable containing the single word 

 "elected" reached me in Baltimore informing me that I 

 had been appointed Savilian Professor of Geometry in 

 Oxford, so that for three weeks I was in the unique posi- 

 tion of filling the post and drawing the pay of Professor 

 of Mathematics in each of two Universities : one, the 

 oldest and most renowned, the other — an infant Hercules 

 — the most active and prolific in the world, and which 

 realises what only existed as a dream in the mind of 

 Bacon — the House of Solomon in the New Adantis. 



To Johns Hopkins, who endowed the latter, and in 

 conjunction with it a great Hospital and Medical School, 

 between which he divided a vast fortune accumulated 



' Inaugural Lecture of Prof. Sylvesi 

 ersity of Oxford, December 12, 1885. 



ed before tlie Un 



