Nov. 26, 1874] 



NATURE 



67 



On the previous page we find his opinion of his own 

 exploit,' for he there tells us: "This calculation is, per- 

 haps, the most rigid geometrical investigation that has 

 ever been applied to an astronomical problem." 



Perhaps our readers will scarcely credit the statement 

 that, notwithstanding this proud confident boasting, there 

 is no investigation at all. All the author does is to draw 

 a circle, which of course he can draw through three points, 

 which are different positions of the earth's pole, and then, 

 because his circle always passes within one second of the 

 different positions of the pole for a couple of hundred 

 years, we are asked to take it as proved that the pole 

 always has been and always must be on this circle. 



The extreme proximity of two curves for a compara- 

 tively short distance is no criterion of their being 

 coincident. 



The author, in the preface to this work, makes some 

 strictures on our remarks on " The Glacial Epoch." In 

 these he mistakes our illustrations for arguments, mis- 

 quotes our objections, and misstates our arguments. It 

 is impossible to reply, and it is perhaps as well ; we have 

 already given too much space to this author. 



OUR BOOK SHELF 



,/ Studi Fisici di Ambrogio Fusinicri : Comineino- 

 rasione per Enrico dal Pozzo di Mombello, Professorc 

 di Fisica nell' Univcrsiid Libera di Perugia. (Foligno, 

 1874.) 

 This dry little book gives an account of the works 

 of Fusinieri which related chiefly to endosmose, capil- 

 larity, adhesion, and other molecular actions ; also to 

 static electricity and to magnetism. He published a work 

 in 1844 on " Molecular Mechanics, and a Repulsive Force 

 in the Ethereal Medium," which we have never seen, but 

 which would surely be of interest now in connection with 

 Mr. Crookes's experiments on repulsion by heat in a 

 vacuum ; in 1846, a memoir on Light, Heat, Electricity, 

 Magnetism, and Electro-magnetism ; in the following year 

 a memoir on Meteorology ; and altogether many small 

 occasional memoirs. The second part of Prof dal Pozzo's 

 works is a critical inquiry into the work entitled " The 

 Unity of the Physical Forces," published in iS64in Rome 

 by Father Secchi ; and the third part contains some 

 biographical notices of Fusinieri. The book is unillus- 

 trated, and has no felicities of style to recommend it ; the 

 students of the Free University of Perugia must be 

 devoted scientists if they purchase the book and manage 

 to read from beginning to end of it. 



LETTERS TO THE EDITOR 



[ The Editor docs not hold lumself responsible for opinions expressed 

 h' Ins correspondents. Aeithcr can he undertake to return, 

 r to correspond with the wrilei's of, rejected manuscripts. 

 Xo notice is taken of anonymous communications.^ 



Royal Agricultural Society and the Potato Disease 



The paragraph which appeared in your last week's issue is so 

 far interesting tnat it amply confnms Ihe expectations of those 

 who have watched the well-nie.ant efforts of the Royal Agricul- 

 tural Society with respect to the potato disease. I wibh to 

 adveit to it lor two reasons. In the first place, it is inteiesting 

 to see the way in which a matter of this kind is regarded by so 

 influential a body. Here is a disease annually eflecting the 

 destruction of a larger or smaller part ot a chief item in the food 

 of the community, which has already produced a famine in one 

 of the three kingdoms, and any year may produce another, and 

 whicli for tlie last thirty years has seriously occupied the atten- 



ton of scientific men throughout Europe. Is it not surpriMne 

 that the Royal Agricultural Society should think the offer of i 

 100/. prize for an essay in any way an adequate method of deal- 

 ing with the subject ? In the first instance, the time for sending 

 111 the essays was actually fixed so as to prevent the compctitoi^ 

 Irum even going over the life history of the fungus dunn" one 

 season before competing. This was pointed out, and the time, was 

 prulonged. But though the comijetition was advertised abroad 

 111 the German papers, notliing of any importance was elicited 

 beyond what was already well known. 



The Society then determined to offer prizes for disease-proof 

 potatoes. The utter futility of this proceeding was clearly 

 obvious to anyone in the least acquainted with the subject. But 

 it was done, and possibly if the " botanic referee " liked travel- 

 ling about the three kingdoms, his time was not wasted. But 

 the result is exactly what it was predicted it would be. 



Now, it seems to me that this spasmodic and ill-considered 

 way of dealing with a serious subject contrasts, to an extent that it 

 is impossible quite to regard with satisfaction, witli the course that 

 would be adopted in such a matter in other countries. It shows, 

 at any rate, how litde the methodical scientific method of inves- 

 tigation is understood by the majority of well-informed English 

 people. 



And this brings me to my second point. The Society, anxious 

 not to be entirely foiled, offered a sum of money to a well- 

 known investigator of the life history of fungi. Prof, de 

 Kary, of Strasburg, to induce him to study the potato disease. 

 Considering that De Bary had already written an admirable 

 memoir on the Peronosporcv, there was a certain simplicity 

 m supposing that the gift of a sum of money would elicit some 

 additional information which his zeal as a scientific investigator 

 had failed to do. If it does, however (and the history of the 

 IWonospora infestans is not perfectly understood), it will be a 

 clear gain ; but when we are told that " Prof, de Bary has 

 worked out the scientific questions that occur as to the origin of 

 the disease," and that "it is owing to a i\xn^\x%(Peron'ospora 

 infestans) which attacks the leaves first, and after absorbing the 

 nutriment of them, utilises the petiole, and thus reaches the 

 tubes " (sic), it is necessary to point out that all this and a good 

 deal more was ascertained by the Rev. M. J. Berkeley in this 

 country, and by Montague in France, and published by the former 

 in a paper contributed to the first volume of the Journal of the 

 Horticultural Society in 1846. 



Nov. 20 w. T. Thiselton Dyer 



Zoological Gardens, Regent's Park 



Having lately visited some of the Zoological Gardens on the 

 Continent, and on my return compared il ose in the Res^ent's Piik 

 with the recollection of the former, I have been impressed that 

 the latter appear to stand in need of much improvement. 



In the first place, to adapt them to modern ideas of sanitary 

 science, we should consider they are much too small in area for 

 the number of inhabitants, especially as several of these are of 

 gigantic size, and many others need naturally much space for 

 exercise. 



The carnivora, when bred and reared in dens of too small 

 extent, begin_ to lose their muscular fulness of body, and what 

 muscle remains becomes degenerated, and some members of 

 their litters, reared in captivity, get affected with symptoms of 

 parai)legia, with weakness in the buttocks and posterior limbs. 



Proprietors of travelling menageries are in the habit of putting 

 their carnivora and large animals through a series of gyvinaslic 

 performances, which will be doubtless of as great benefit to their 

 health as they are) to the human species, and ought therefore 

 to be introduced into our Zoological Gardens. 



The antelope and deer tribes, being of nomadic disposition, 

 should have much more space allotted to them than there is at 

 present in the Gardens, where should be provided means for 

 grazing and browsing in the open air, in full sunlight, and vvitli 

 bee exposiire to the winds, to ensure healthy digCbtion and com- 

 p ete aeration in the lungs. 



In a city so well provided with water as London is, one must 

 be surprised at the scantiness of the supplies afforded to some 

 quadrupeds and birds, whereby what little exists very soon gets 

 soiled and unfit for bathing and drinking purposes. These 

 basins and ponds are seldom to be seen filled with aught else 

 than ditch water, and are as dirty as horse ponds, whereas there 

 might easily be designed and constructed a plan for a constant 

 supply of fresh water to run in, and the foul water out, and thus 

 ensuie purity and cleanliness. 



