Oct. 24, 1 872 J 



NATURE 



515 



An Additional Note on American Arrowheads 



As Mr. Evans has commenced his remarks on North Ameri- 

 can arrowheads with the assertion, "A prevailing type," S:c., it 

 naturally leads one to conchide that that form to which he refers 

 is " the " prevailing type. I judge, further, that by " pre- 

 vailing," he means "predominant," i.e., in excess of other types 

 or shapes of these relics. I do agree with Mr. Evans that it is 

 one of the principal forms, but not so far a "prevailing " type as 

 to merit tlie assertion of Mr. Evans, made as that assertion is. 



As to the leaf-shaped form, I have but to remark that, in 

 my own collecting experience, the true leaf-shaped, i.e., the 

 rounded-based, straight-sided, acutely-pointed form, such as 

 Mr. Evans's Fig. 2S2, constitutes about 4i per cent, of those 

 gathered in my own neiglibourhood ; and this I know to be the 

 experience of other collectors, in other and distant localities. 

 This, I submit, is sufficient to show that this form is not even 

 "comparatively rare," but may be better described as "not 

 uncommon." 



And so far as workmanship is concerned, I have only to say 

 that if narrow, thin barbs, acute points, sh.irp edges, and smooth- 

 ness of the broad surfaces of arrowheads, constitute what has 

 been termed " delicacy of workmanship, " then the American 

 forms in horn-stone, j.-rsper, chert, quartz, agate, and some finely- 

 grained slates, cannot be excelled liy similar relics found else- 

 where, or made from other material. JThis remark I base on 

 the specimens collected by myself here in New Jersey, which 

 State is not the best locality, by any means, for gathering these 

 objects ; and I have found that the western, northern, and 

 southern specimens have excelled those I have collected here 

 at home. 



From the above paragraph I have purposely omitted the mineral 

 obsidian, because the arrowheads of this material excel all others 

 wheresoever found, and I wish to make good my assertions 

 without the help of Californian specimens. 



I take the liberty of referring those persons interested in 

 these matters to a large series of arrowheads collected here in 

 New Jersey, and now in the collection of Sir John Lubbock. If 

 some of these are not equal to any Enghsh specimens, I must 

 simply "give in." Chas. C; Abbott 



Trenton, New Jersey, U.S.A., Oct. 10 



Merrifield on the Deviation of the Compass 

 As a review of my little manual on "Deviation," &c. , has 

 appeared in Nature for October 17th, in which I am accused 

 of having " written with looseness and inaccuiacy," perhaps you 

 will kindly allow me a small space to answer my critic. He 

 has selected a most unfortunate example to bear out his asser- 

 tion ; and I contend for the accuracy of my statement. " Ver- 

 tical iron, at the same place, will produce the same deviation in 

 whatever direction the ship's head may be." Here I do not 

 pretend to say (as my reviewer insinuates), that the whole devia- 

 tion is the same in every position of the ship's head ; but I 

 maintain that that part due to vertical iron remains constant for 

 the same place until a change of secular variation becomes cog- 

 nisable. I am at a loss to discover either looseness, inaccuracy, 

 or substitution of cause for effect in what follows, and I am in- 

 clined to think, if any exists, it must be on the part of my 

 reviewer 



Again, I am not aware of any "singular statements and con- 

 ceptions" in the larger work on "Navigation and Nautical 

 Astronomy," which are at variance with the matter contained in 

 the small manual under consideration. Perhaps you will kindly 

 permit my reviewer to mention some. 



I grant there may be differences of opinion on the merits of 

 any work (as is fully proved in the present instance) ; butjwhen 

 public statements are made of " inaccuracies," these should either 

 be substantiated or withdrawn. 



John Merrifield 

 Navigation School, Plymouth, Oct. 19 



Earth Currents 

 It may be interesting to record that during the past few d.iys 

 we have been subject to electric storms, I think I may say un- 

 paralleled in their frequency, intensity, and duration. On 

 Oct. 14a severe one raged from g.30 a.m. to I p.m., and in the 

 evening from 10.20 I'.M. to past midnight. On the 15th a still 

 more severe one raged from 9.30 A.M. to I p.m., and in the 



evening from 7 P.M. to 9.5 p.m. On the 17th inst. the currents 

 were very embarrassing from 11.20 A.M. to 12,45 p.m., and from 

 2.10 to 9.0 p.m. ; and on the iSth tliey were again troublesome. 



They differed but little in their character from those usually 

 observed, the currents continually varying in intensity and dura- 

 tion during the periods named. The interruptions to business 

 on the 15th were serious, and many stations could only be com- 

 municated with by looping the wires, when more than one 

 existed, into metallic circuits. Circuits running east and west 

 were mostly affected, those running north and south, for instance, 

 between London and Brighton, being but little disturbed. I 

 regret to say that no precise measurements of the strength of 

 these currents have yet reached me. 



Soutliampton, Oct. 21 W. H. Preece 



Aurora Borealis 



On .Saturday, Oct, 6, I was walking in our large playground 

 witlt a friend, about 8.40 p.m., when we saw above us a mag- 

 nificent red " way " whose direction was E. N. E. When we 

 first looked, this broad band was bifurcated towards the E. end, 

 one fork going more to the east, and the other to the north. In 

 a minute or two this bifurcation disappeared, and in three minutes 

 more the whole had disappeared, leaving the sky as before. 

 It could be nothing but an aurora ; at any rate, it was not the 

 light of any fire, it was too magnificent, and for the time that 

 it lasted of too great a length. I took no notes at the time, but 

 feel that I have given you a correct account of the phenomenon, 

 as far as it goes. 



Christ's Hospital, Oct. 20 F. Jeffrey Bell 



Ocean Currents 



It is to be regretted that the correspondents of Nature, who 

 for some weeks past have been writing on the subject of Ocean 

 Currents, should ignore tlie consideration that it is primarily a 

 question of geographical fact, and that any theory which runs 

 counter to that needs no more elaborate confutation than a bare 

 statement of the fact, supported, if necessary, by authoritative 

 evidence. Thus, then, when we find the effect of the earth's 

 rotation put forward, in the way it has lately been, by Mr. 

 Ferrel and Prof. Everett, it is quite needless to examine the cal- 

 culations which have been adduced ; it is sufficient to say that 

 the conclusions arrived at are contrary to geographical fact ; that 

 currents do not by any means universally turn to the right in 

 the northern, or to the left in the southern hemisphere ; — to 

 name a few amongst many, the Gulf Stream turning to the left 

 round Cape llatteras, and again towards the coast of Ireland, 

 Rennell's current, the Agulhas current, the Cape Horn current 

 as it turns south near Chiloe, the current through Behring's 

 .Strait, are cases in point, currents turning in a manner exactly 

 opposite to that deduced from the theoiy. 



Similarly, when Dr. Carpenter, whether supported or not by 

 several distinguished phycisists, argues from the effect of great 

 differences of temperature in a small trough, as to the effect of 

 much smaller differences of temperature in the incomparably 

 larger ocean, it is unnecessary to follow him into his reasonings, 

 for the conclusion, as he has lately stated it, that there is "neces- 

 sarily an upper flow from the equator towards the poles," is 

 geographically false. Over a very great part of the North Atlan- 

 tic there is no prevailing set at all ; in the South Atlantic and 

 in the South Pacific the set has a general though slight tendency 

 towards the north ; the East Greenland current, the North 

 African current, the South African current, the Peruvian current, 

 and many others, run strongly towards the equator ; there is 

 nothing at all resembling a general " upper flow from the equator 

 towards the poles." 



As a question of abstract mathematics, Mr. Ferrel Is un- 

 doubtedly at liberty to prove that every current in the northern 

 hemisphere turns to the right, as much as he was, a few years 

 ago, to prove that there is no air within some twenty or twenty- 

 five degrees of the poles ; and as a point of experimental science. 

 Dr. Carpenter's illustrations are pretty, and can be understood 

 without the authority of tlie distinguislied men whose names he 

 brings forward ; though I should be loth to believe that Mr. 

 Mawksley, or any other experienced hydraulic engineer, would 

 agree with liis idea that water will always find its own level. 



But the application of the mathematical problem or the experi- 

 mental illustration to the case in point is quite a different thing ; 



