June 7, 1883] 



NATURE 



i=5 



The objection started is a serious one, for, if the deductive 

 method is wrong at all, it is so absolutely, and must on no 

 occasion be allowed a place in scientific reasoning, but — without 

 any half-measure allowances — must be excluded altogether as a 

 false and dangerous element of philosophy. If, on the other 

 hand, we take exception, as I think we may do, to the ex- 

 ponent's opening expression, — " having formulated a few 

 fundamental assumptions, to spin out from these explanations of 

 what we see in the world about us ... is merely a literary 

 performance," — as misleading in its main idea, we may still hold 

 the method to be a perfectly scientific one. 



The evolutionist, who has once ascertained by various careful ex- 

 periments and extensive researches that there is a direct natural 

 sequence of events in connection with certain phenomena, may 

 be allowed to adopt set principles as recognised laws of action, 

 fully as much as Euclid in the demonstration of problems from 

 his formulated axioms. But perhaps Prof. Dyer's argument 

 rests in reality upon his use of the word " assumptions," and 

 thus his objection is merely urged against the false method 

 assumed in his premise, rather than against deductive biology as 

 a method of procedure, as he would have us believe. And so 

 far, of course, every one will readily enough accept Prof. Dyer's 

 remark as it stands. 



But the conclusion that " the deductive method is a bad way 

 of solving morphological pro'denis " is opposed to all the evi- 

 dence of Darwin himself, who constantly applied those well- 

 tested principles which he had discovered even by this very 

 method, and upon the bases of such fundamental truths it was 

 that he reared his wonderful system. Are not the studies ol 

 comparative embryology and osteology, of comparative histology 

 and biology, each founded entirely upon the method of deductive 

 analogy ? 



As another sufficient w itness, Mr. Wallace may be quoted as 

 having adopted the same course with such remarkable results, 

 and throughout his writings bears testimony to the value of 

 deductive inference as a method of procedure, and I will de- 

 duce a couple of sentences taken from his work on " Island 

 Life," bearing directly upon our point. 



" On the theory of evolution," he says, "nothing can be more 

 certain than that groups now broken up and detached were once 

 continuous, and the fragmentary groups and isolated forms are 

 but the relics of once widespread types which have been pre- 

 served in a few localities where physical conditions were espe- 

 cially favourable, or where organic competition was less severe. 

 The true explanation of all such remote geographical affinities is 

 that they date back to a time when the ancestral group of which 

 they are the common descendants had a wider or a different dis- 

 tribu ion," &c, p. 296. And, in summary of the chapters on 

 M dagascar, Mr. Wallace remarks : " The method we have f >1- 

 lowed in these investigations is to accept the results of geological 

 and paUeontological science, and the ascertained fact as to the 

 powers of disper>al of the various ani ual groups ; to take full 

 account of the laws of evolution as affecting di tribution, and of 

 the various ocean depths a^ implying recent or remote union of 

 islands with their adjacent continents ; and the result is that 

 wherever we possess a sufficient knowledge of various classes of 

 evidence we find it possible to give a connected and intelligible 

 explanation of all the most striking peculiarities of the organic 

 world" ("Island Life," p. 419). We may then assuredly de- 

 cide that the deductive sys'em of logic, — the use without abuse 

 of certain known factors, — instead of being in any way "bad," is 

 (granting always that the general laws of Nature applied are 

 sufficiently trustworthy) found to be even superior to the older 

 and tardier processes of induction, to which the mere collectors 

 of the facts dealt with have limited themselves, and has proved 

 itself to be the only means of elucidating many of those abstruse 

 problems, the solution of which has been conducive of such 

 immense gain to the scientific philosophy of our day. 



William White 



Science and Art 



As a rule it would be the extreme of absurdity for me to 

 venture an adverse remark on the criticism of an art critic 

 on paintings, yet there is one single exception regarding which 

 I may perhaps be permitted to say a word nr two. 



In the very interesting critique on some pictures in the Royal 

 Academy, written evidently by a master-hand, there is one 

 picture — No. 764, "a snowstorm" (see Nature, vol. xxviii. 

 p. 76), not only somewhat severely, but I think unjustly or 



incorrectly, commented upon, because " there is not a single 

 snowflake to be seen in the first twenty yards." 



I have witnessed and been in the midst of many snowstorms 

 in America, and some in Scotland. In a large proportion of 

 these not a snowflake was to be seen, the snow being in very 

 minute particles, so fine as to penetrate all openings in the cloth- 

 ing, however small. Snowstorms of this kind are the most 

 dismal, bitter, and chilling of any. 



On looking at Mr. Farquharson's picture, I was struck with 

 its resemblance to a most unpleasant evening and night spent in 

 the hills between the Coppermine River and Great Bear Lake, 

 about 50 miles north of the Arctic circle. It being early winter, the 

 weather was not verv cold, but there was a combination of fog, 

 fine snow (no snowflake-), and snowdrifts, which produced one 

 of the most dismal and dreary scenes imaginable. 



4, Addison Gardens, May 29 John Rae 



Transit Instrument 



In your issue of the 17th ult. (vol. xxviii. p. 51) you notice 

 a cheap form of transit instrument introduced by me, and you 

 point out the defect that no means are provided for placing the 

 cross wires truly vertical. In all the most recent instruments 

 which have been made this difficulty has been met by an arrange- 

 ment which answers so effectively that I think it may interest 

 others beyond those who are likely to use the in truuient in 

 que-tion. 



I employ the ordinary diaphragm with the usual four stretch- 

 ing screws, and the c illimation is correc ed in the usual manner 

 by these screws. Into this diaphragm I insert a tube with a very 

 fine screw, on the outside of which is fixed a plate carrying the 

 cross hairs ; by screwing this tube in or out the focus may be 

 perfectly adjusted for objects at an infinite distance, while a 

 slight additional movement to the right or left enables one at the 

 same time to adjust the cross hairs truly vertical. 



Latimer Clark 



Sea-Shore Alluvion, Dungeness 



Reverting to an article in your journal of July 28, 1S81, and 

 a letter of mine in that for April 20, 1882, the following at the 

 present lime may be of interest : — 



As regards the local wasting away in the bays east and west 

 of Dungeness and the redistribution of the materials at Light- 

 house Point ; — 01 the west side the whole margin from Rye 

 Bay to " Dei ge Marji Gut," a ■ Stance of eight miles, has 

 receded of late years ; this is shown by the fact that the Denge 

 Marsh authorities have recently erected a clay counter sea-wall 

 at the back of the modern shingle "fulls" in front of the 

 "Midrips" and "Wicks" (small land-locked pools of water) 

 to check the overflow of the sea in south-west gales. This action 

 is felt to the eastward in front of the "Holmstone," the Lydd 

 coasiguard station, and up 1 1 " Denge Marsh Gut," eastward of 

 which we have modern "fulls," — : he resultant in part of this 

 waste, overlapping and adding to the south-east outline of the 

 " Ness " or extreme projection of this natural mole of shingle, 

 and thence travelling northward until reaching "Great Stone 

 End," which forms the southern boundary of Romney " Hoy " 

 or Hay, northward of which Dymehurch Wall, an artificial 

 stone-faced sea-wall three to four miles in length, is sufficient 

 evidence of the modern local waste a d neces-ity for sea-defences 

 to the rich grazing district of Romney Marsh. Still further 

 northward the sea-wall recently constructed by the municipal 

 authorities of Hythe is equally suggestive of this recession. 

 Going no further back than Cole's survey of 1617, we have a 

 stains quo ante very nearly, as regards outline from Rye Kay to 

 within two miles of the lighthouse, and this accompanied by a 

 local south-east increase and movement around the lighthouse, 



