458 



NATURE 



[March 20, 1879 



Experiment with a Vacuum Tube 



A TUBE like a radiometer tube contained a concave metal 

 disk within the bulb ; this disk could be connected with the pole 

 of an induction-coil, and about a quarter of an inch above it was 

 a small wire which could be connected with the other pole. The 

 bulb was exhausted to such a point that a 5-inch jspark could not 

 pass from the wire to the metal disk. The wire and disk were 

 connected for several minutes with an induction-coil giving 4^ 

 to 5-inch sparks ; although no spark passed between them, the 

 glass on the side of the bulb, which v/as j»s( in the focus of the 

 metal concave disk, ivas melted, and the pressure of the external air 

 forced the melted glass inward, and a minute hole was formed, 

 of course destroying the vacuum. The diameter of the hole was 

 about that of the finest sewing-needle ; it was in the centre of a 

 depression in the side of the bulb about a tenth of an inch in 

 diameter. H, Alfred Cunnington 



Devizes, February 28 



[Having succeeded in melting platinum by the heat of molecular 

 impact (Proc. Roy, Soc, No. 191, p. no, and Nature, vol, xix. 

 p. 137), it is not surprising that the heat is sufficient to melt glass 

 when the focus falls on it. In a paper communicated to the Royal 

 Society in November last, now being printed in the Philosophical 

 ■ Transactions, I mentioned that by drawing the focus on to the 

 side of the glass tube by means of a magnet, the glass became 

 heated to redness. In December I wrote to Prof, Stokes that I 

 had melted up a piece of Gorman glass in the focus of the rays, 

 and at the same time I sent a piece of the melted glass to my 

 friend Mr, Sorby, of Sheflfield, for microscopic examination, as 

 the fusion in vacuo had produced an unusual appearance on the 

 surface of the glass. — William Crookes.] 



Tides in the Bay of Fundy 



Having resided for some years in the neighbourhood of this 

 bay, I am able to give a little information respecting its tides. 

 The bay splits into two at its inner end. One of these branches 

 leads through a narrow channel into the broad basin of Minas. 

 The other, called Chegnecto Bay, is not interrupted by any such 

 contraction, and is therefore more favourable for the formation 

 of very high tides. This bay itself divides at its upper end into 

 two, and one of these, called Chepody Bay, contracts very 

 gradually for some thirty miles inland, forming the estuary of 

 the Petitcodiac River, This is the place where the highest tides 

 occur, and as far as I have been able to learn, their maximum 

 height is 70 feet, A powerful "bore" is formed by the 

 incoming waters. The captain of the steamer Emperor, which 

 plied between St, John, N,B., and Windsor, N.S,, informed me 

 that the highest tide in any part of Minas Basin was about 55 feet. 

 This would probably be at the head of Cobequid Bay, near Truro. 

 Noel Bay, which is mentioned in Dr. Haughton's letter (Nature, 

 vol. xix, p. 432), is in Minas Basin, rather more than half way 

 from its narrow mouth to the head of Cobequid Bay. If the 

 range here at ordinary spring tides is 50-5 feet, any one looking 

 at the map and knowing the effect of funnel shaped estuaries, 

 would be prepared to learn that there is a range of from 60 to 

 70 feet in Chepody Bay and the estuary of the Peticodiac, at 

 strong springs, J, D, Everett 



Malone Road, Belfast, March 14 



End-on Gas-Vacuum Tubes in Spectroscopy 



While nothing will give me greater pleasure and confidence 

 in my own worked-out views than to learn, as you intimate in 

 the editorial note (Nature, vol, xix. p, 400), that so able a work- 

 ing scientist as Dr, Van Monckhoven had preceded me in point- 

 ing out the value of end-on gas-vacuum tubes, and had sent speci- 

 mens similar to mine to several observers in England, allow me 

 to inquire where I can find any published account in this country 

 of his tubes, the parties to whom they were sent, and the work 

 accomplished with them ? And why, also, if the said tubes were 

 found by those gentlemen as intensely superior for spectroscopic 

 results as mine are proving themselves — they have not yet been 

 described in any of the latest London books I have been able to 

 look into on spectroscopy, natural philosophy, electricity, and 

 instrument-makers' price lists, though the old, pale, imperfectly- 

 lighted, transverse-vision tubes are referred to in all ? 



Your obliging answer to these questions will evidently be of inte- 

 rest to Dr. Van Monckhoven, as well as myself, while it will also 

 have a far wider and more important bearing for many persons 



in Scotland. For they, conscientiously striving by all recognised 

 public methods of study to keep up with progress in the south, 

 and not having heard of end-on gas-vacuum tubes for the spec- 

 troscope before my recent paper on them, would very much like 

 to have thereby and therein a practical demonstration of what a 

 thing, and a good thing too, being, as you say of this, "already 

 well known in England," really consists in ; and to what extent, 

 therefore, every member of the community here ought to have 

 similarly knovim it on the loth inst., and myself nearer to the 

 same date in 1878, when M, S aileron made the first examples 

 for me, on my then supposed new idea. PiAZZi Smyth 



Edinburgh, February 28 



[Dr. Van Monckhoven writes that his new tubes were described 

 to the Belgian Academy of Sciences in 1877, in a note, a copy 

 of which he sends us. He states that he sent some of these 

 tubes to Mr. Dallmeyer, who gave them to various English men 

 of science. They give, he states, about 100 times more light 

 than the ordinary spectrum tubes. — Ed.] 



Intellect in Brutes 



Dr. Rae has so fairly disposed of Mr, Henslow's examples 

 of so-called "practical and "abstract reasoning" that further 

 comment is unnecessary. As, however, the subject of intellect 

 in brutes is on the tapis, I will give an instance of sagacity in a 

 dog that finally set at rest any doubts I ever entertained that the 

 difference between human and animal intelligence is one of 

 degree only. 



If you have space for it, the accompanying plan will be of 

 great value in describing the circumstances. 



Mr, J, W. Cherry, of the Madras Forest Service, was owner 

 of the dog in question, a bull terrier, called "Bully." We 



lived in the bungalow (a), the compound of which was bounded 

 south and west by public roads (d c) and (G F c) both leading to 

 the cantonment of Mangalore in the direction C. There were 

 three gates into the compound at (c) (d) and (g), the main ap- 

 proach to the Bungalow leading over a bridge (b), that spanned 

 a branch public road (f d). The compound was filled with 

 trees and shrubs, and bordered by dense lantana hedges, so that 

 with the exception of a portion of the western road at F, neither 

 of the cantonment roads were visible from the bridge, nor could 

 the foot-paths (a) and [b) be seen thence. 



Now Bully had a lady friend (canine) living in the canton- 



