Sept. 20, 1877] 



NATURE 



439 



be inferred, an indication of the presence of some physical cause 

 tending to increase the rainfall in years of minimum and diminish 

 it in years of maximum solar maculation. 



Bankipore, Patna K. D. Archibald 



The Australian Monotremes 

 It is certainly news to me, and I believe to most other 

 European naturalists, that Tachyglossus and Ornilhorhynchus 

 occur in Norlhern Queensland. Perhaps W. E. A. will kindly 

 state, for our information, the exact spots where they have been 

 discovered and their extreme noithern limit, so far as this has 

 been ascertained . 



W. E. A. speaks of an adult female Echidna {sive Tachy- 

 glossus) having "a fine healthy young one in the pouch." Is 

 there not some error here, as the monotremes have, strictly 

 speaking, no marsupial pouch ? P. L. S. 



With reference to the existence of Tacliyglossus (oliin Echidna) 

 in North Australia, and the recent discovery of one (or posMbly 

 two) species in New Guinea, the following account, which I 

 lighted on a few evenings ago, when looking over an old volume 

 of the Field, seems to be of sufficient interest to warrant its 

 transfer to the pages of Naturf. The account in question 

 occurs in an article "A Week at Plain Creek, Queensland," by 

 Mr. E. B. Kennedy, which appeared in the issue of that journal 

 for .September 20, 1873. It runs as follows : — " . . . Whilst 

 so engaged we heard our dogs making a tremendous noise, high 

 up the bank in the scrub, and upon going to ascertain the cause 

 found them scratching, yelling, and pulling at a porcupine which 

 was half imbedded in a hole ; we were at least ten minutes 

 digging him out with sharp-pointed sticks, such was his tenacity 

 in holding on and burrowing. The quilk were not nearly so 

 long as the Cape of Good Hope species (of course a true 

 llystrix), an<.l he differed from that quadruped in having a sort 

 of beak instead of a regular j.aw. " It is to be regretted that Mr. 

 Kennedy did not preserve his specimen, which was ultimately 

 cooked and eaten ! I should have mentioned that Plain Creek 

 lies in 21 lat. S., so that this is certainly the northernmost 

 locality on the Australian continent, where we have certain 

 knowledge that the Ecliidna occurs. As we now know that 

 many North Australian species of birds range also into southern 

 New Guinea, it would hardly be surprising if the Tachvglos^us 

 of the Fly River and south New Guinea were nothing more than 

 the well-known Tachyglossus hystrix. It is to be hoped that 

 this point may soon be solved by the arrival of specimens from 

 both localities. W. A. Forbes 



English Names of Wild Flowers and Plants 



To all who are interested in the history of the English 

 language the derivations proposed for the vernacular names of 

 many plants in the Rev. W. Tuckwell's lecture (see Nature, 

 vol. xvi. p. 385) will be highly appreciated. And even in the 

 few cases where the etymologist may feel doubtful as to the 

 verisimilitude of the suggested pedigree it will for the most part 

 be difficult to propose another with any great confidence. 



There is, however, one of these doubtlul cases, the derivation 

 of woodruff from wood-roue, in lieu of which I have to offer a 

 conjecture which appears to need no lengthy argument to insure 

 its acceptance. 



Is not the ruff of woodruff identical with the riff of sherriff? 

 Is not, in short, the woodruff the wood-reeve, just as the sherriff 

 is the shire-reeve ? That the German wald-meister has the same 

 connotation and is applied to the same plant is evidently a 

 striking confirmation of this view, and it would be interesting to 

 know whether the word wald-graf (z.t'., wald-ge-raf = wood-y- 

 reeve), or any equivalent form, is to be met with in high or low 

 German literature. 



I used to be told by a school-fellow that the way to spell 

 woodruff was — 



Double U, double O, double D, E, 

 Double K, double O, double F, E. 



Even under the disguise of woodderrooffe, however, the origin 

 of the word is perceptible. 



As regards the main purpose of the Rev. W. Tuckwell's 

 paper, I feel strongly that scientific accuracy is compatible with 

 a much freer use of vernacular words than is customary amongst 

 us, and that their adoption by science teachers would remove a 

 great stumbling-block from the path of learners. 



Manningham, September 10 J. Willis 



Some of the Troubles of John O'TooIe respecting 

 Potential Energy 



"It is the people's ri^lit to demand of their teachers that the 

 information eiven them shall b^, at least, definite and accurate 

 a*; far as it goes," and " whenever there aooears to be a contusion 

 about fundamental principles it is the dtiy of a scientific min to 

 endeavour by all means in his power to remove it." These are 

 the words of one of the teachers.^ I am one of the people- -as 

 indeed, my name testifies, Toole ( Tuathal) being the Irish 

 equivalent of the Latin Publius — and I would now, on hehaU of 

 myself and every brother Publius, assert our above "right" in 

 respect of the matter now in hand, and demand the performance 

 by the doctors of their corresponding "duty." Now there is 

 much " confusion about the fundamental principles " of phvsical 

 Energy in the minds of the public who care about such things ; 

 and it is principally, though I admit not entirely,' the doctors 

 who are to blame for this. Their own ideas on the subject being 

 so clear and correct they are superior to the phraseology they 

 use respecting it, and they are not injuriously affected thereby ; 

 hut those who are dependent on that phraseology for their 

 knowledge are in very different case. Let me, as one of the 

 latter, point out some of the perplexities under which we labour 

 from no fault of our own, and which we should be spared 

 if our teachers would only condescend to use their words dis- 

 creetly and consistently. It may be well to premise that we 

 know the definition of physical Energy, which is — "the power 

 or capacity of performing work ; " and that we are not now 

 m.iking any confusion between Energy and force. 



The word "potential" has two very different meanings — (l) 

 Of, or belonging to, potency or power ; (2) Existing in posse, or 

 in possibility, as opposed to existing iti esse, or in actuality ; 

 and the expression, "potential Energy," can have no less than 

 three references or meanings, which we shall mark with A, B, 

 and C > and each meaning has its own proper inconveniences 

 independent of the perplexities arising from their mutual 

 relations. 



A. — Potential E., as meaning '' Energy existing in posse." 



The phrase "potential E." is in the first place very gene- 

 rally intended to mean E. existing /k posse, according to one 

 proper signification of the word "potential." The phrase was 

 first used by Rankine,^ and apparently in this sense ; he con- 

 trasted " potential " and "actual" E. This antithesis is still 

 very generally implied and sornetimes expressed. Clerk Maxwell 

 tells us ^ (the statement being repeated only last year^) that 

 " potential E." "signifies the E. which a system has not in actual 

 possession, but only has the power to acquire." Worm^ll says ® 

 — "It has been aptly called possible or potential E. , because it 

 represents the power the body has of acquiring actual or kinetic 

 E." Many of our doctors use the phrase " potential E." with- 

 out explaining it, and of course, unless there be some particular 

 reason to the contrary, such must be understood to give it, as 

 one of its significations, at least, the original meaning intended 

 by its proposer (or if not they are guilty of a very misleading 

 omission, iitritm horuin mavis acerpe) ; and this is especially 

 undeniable in the case of those who apply the title " actual " to 

 the other type of E. Balfour Stewart, though he seems to have 

 quietly dropped the name " potential,"" has really retained the 

 idea implied thereby, for he still habitually calls the other type 

 of E., that of motion, " actual E.," as its disUnguishing title. 

 Moreover, this idea is involved in other statements, &c., of our 

 teachers. For instance, we occasionally find language used 

 which seems to imply that potential E. must first emerge as 

 actual E. before it can produce work, as by Di-schanel,' by 

 Dunbar Heath,^ and by Balfour Stewart.'" OI>servr, also, the 

 expression "E. of actual motion," which is frequently iispj hy 

 the last-mentioned doctor,'' and accepted at least b Tait. " " E. 



■ Tail Evenire lecture during meeting of Brit. Assoc at Glasgow in 

 1876 Naturr, Sept 2t, 1876. 



" That brother Publius who wrote the article on Tyiidall's " Heat," in 

 Black-Mood's Ma^., December, 1863, was partly responsible for his own 

 confusion about Energy. 



3 Pliil Mag., February, 18=3. He says : " All conceivable forms of E. 

 may be distingtiished into two kinds, actual or sensible, and potential or 



4 "Theory of Heat." p. 91, 1871. 



5 "Matter and Motion," p. 81, 187S. 

 c> " Dynamics," p. 185. 



^ At least it never occurs in his " Conserv. of Energy," 1S74, though 

 frequently in " Elem. Physics," 1S70. 

 8 " Nat. Phil.," p 78, edition of 1870. 



«" Energy," p. 64. ■»" Elem. Physics," pp. 104-106. But see p. 360 

 " " Conserv. of Energy," p. 25, and elesewhere. 

 '- " Unseen Univ." (last edi'ion), p. 109, twice. 



