Jan. 6, 1881] 



NA rURE 



217 



they have brought to bear the scientific trainin;j they had 

 received at their universities and polytechiii': schools. 

 Thus they have already, in many fields formerly remu- 

 nerative to British manufacturers, distanced the latter, 

 immensely aided though these be by their long occupation 

 of the ground and by permanent natural advantages, such 

 as cheapness of coal and of freight, superior command of 

 capital, &c., and this is likely to go on to an increasing 

 extent if many British chemical manufacturers decline to 

 profit from a scientific study of their respective branches. 

 This is all the less excusable, as England fro;n of old has 

 been a stronghold of scientific chemistry, an 1 can hold 

 its own against the whole world in that respect." 



To these words I will only add that one of the best 

 possible signs of advancement in the study of science so 

 necessary for the permanent well-being of our manufac- 

 tures would be to find well-thumbed copies of Dr. Lunge's 

 three volumes not only on the alkali-maker's shelves, but 

 in the house of every manager, and on the table of every 

 free library in the manufacturing districts. 



H. E. ROSCOE 



OUR BOOK SHELF 

 Aide-Memoire dii Voya^cur. Par D, Kaltbrunner. (Zurich : 



Wurster et Cie., 1881.) 

 This is a sort of supplement to the " Manuel du Voy- 

 ageur" by the same author, noticed in these pages at the 

 time of its appearance- The present volume may be 

 described as a collection of constants in all departments 

 of science likely to be of service to the scientific traveller, 

 and indeed to students of many kinds. It contains a 

 series of sections in geography (mathematical, physical, 

 and political), geology, biology, and anthropology. To 

 each section is prefixed a list of works to be consulted on 

 the particular subject, numerous plates and maps, an 

 inde.\, and a table of authors whose works are cited. 

 The whole work seems to us well put together, the infor- 

 mation really useful, and, so far as we have tested, trust- 

 worthy, though the lists of works are not always so com- 

 plete as they might be ; this can be easily amended in 

 subsequent editions. To all interested in geography in 

 its widest sense, the work must prove of real service. 



LETTERS TO THE EDITOR 



[The Editor does not hold himself responsible for opinions expressed 

 by his eorrespondcnts. Neither can he undertake to return^ or 

 to correspond with the writers of, rejected manuscripts. No 

 notice is taken of anonymous communications. 

 The Editor urgently requests correspondents to ktcp their' letters as 

 short as possible. Ihe pressure on his space is so great that it 

 IS impossible otherwise to ensure the appearance even of com- 

 munications containing interesting and no7.'el facts. '\ 



Geological Climates 



I SHOULD not say more on this subject, but that the last para- 

 graph of Mr. Starkie Gardner's letter seems to imply that I have 

 adopted some of his views with mt ac'^nowledgiiient. Now I 

 certainly read his article in Nature of December 12, 1878, with 

 much interest and profit ; but, as regards the special question of 

 the cause of the mild climates of Eocene and Miocene time^, I 

 entirely disagreed with his views, as is sufticien'.ly shown by my 

 recent letter in Nature. I quite admit that the closing up of 

 the North Atlantic between Europe and North America might 

 have considerably rai ed the temperature of Britain, hut it would 

 just as certainly have rendered tlie Arctic regions even colder 

 than they are now, by shutting out the Gulf Stream, whereas all 

 the evidence |ioints t ) con'inuous mild Arctic climates through 

 Cretaceou-:, Eocene, and Miocene times. Again, though I admit 

 that there has probably, on more than one occasion during the 

 Tertiiry period, been a land connectim between North-West 

 Europe and North-East America, yet the peculiar dis ribution of 

 the Tertiary mammalia of Europe and North America indicates 

 that such connection was exceptional, and only endured for very 



short periods, the rule being a separation like that which now 

 e-xists. I c luld therefore only have qu jted Mr. Gardner's view 

 to disagree with it ; and I did n it think it advisible to encumber 

 the ex;iosition of my own the jry with more references of this 

 kind than were absolutely necessary. I may add, that the 

 i-xten-ion of the Miocene Arctic flora to Grinnell Land since 

 Mr. Gardner's article appeared, renders his views still more 

 untenable. Of course I here refer to my chapter on "Mild 

 Arctic Climate? " in "Island Life." In my letter to Nature I 

 confined myself strictly to the point raided by Prof. Haughton, 

 which I did not consider had been adequately met by Mr. 

 Gardner's hypothesis. Alfred R. Wallace 



Is your correspondent, Mr. Ingram of Belvoir Castle, quite 

 certain that he has not confused the Araucaria Cunninghami of 

 Queensland with Cunninghamia lanciolaia of China ? The names 

 are misleading. H. King 



Chithurst, Petersfield 



Temperature of the Breath 



From time to time during the past few months letters on 

 " the temperature of the breath " have appeared \\\ Nature, 

 and some conjectures have been advanced regarding the cause 

 of the high temperatures produced by breathing on thermometers 

 envel iped in silk or other materials. 



One of the corre-pondeuts suppo-ei that the high tempera- 

 ture thus produced indicates a cool ng action of the breath. 

 The refrigerating agency of re-piralio 1 by the heating of 

 respired air and by evaporat on from the lungs ii sufficiently 

 well ku jwn, and has been calculated by Helmholtz ; but it is 

 scarcely logical to ascribe to the breath a temjierature so ob- 

 viously produced by the intervention of another agent, and this 

 hypothesis would involve the rejection of all obser\'ations 

 hitherto made by physiologists ou the temperature of the breath 

 and of the blood 



A icw lines which appeared in Nature of October 7 in- 

 dicated what appeared to me to be the simple and philosophi- 

 cal explanation {i.e. hygroscopic condensation) of the phenome- 

 non under discussion. The hit;her temperatures produced in 

 dry than in wet weather, and by some materials than by others, 

 di-tincily point to the hytrroscopic state and nature of the 

 material as the modifying influences. 



The question is entirely physical, and not physiological. 

 Wrapping the thermometer i. a new factor in taking the tem- 

 perature of the breatli, and is, primil facie, the cause of the 

 hi^h temperature. S ime further experiments which I have 

 just completed place the matter beyond all doubt. Not to 

 occu]iy your space with unnecessary details, I give only an 

 outline of them : — 



I A current of air directed upon the bulb of a naked thermo- 

 meter caused no appreciable rise ; neither did the mercury rise 

 when the bulb was enveloped in silk ; but when it was env loped 

 in (/;/(•</ silk it rose several degrees (The silk was dried by 

 heat, and allov^ed to co 1 in a s'oppered battle.) 



2. Three thermometers — (l) bulb naked, (2) bulb wrapped in 

 silk, (3) bulb wrapped in dried silk — placed in a current of hot 

 damp air for s^me minutes, marked respectively 116°, 120°, and 

 123° F. 



3. Two thermometers, one naked, the other wr.ipped in silk, 

 were placed in a flask, with their stems pas ed through the cork. 

 The flisk was then immersed in hit water (about 150° F.). The 

 naked thermometer rjse rapidly, the covered one very slowly. 

 After tweuty minutes the temperature of the water was 120", 

 and the naked thermometer marked 112°, while the covered one 

 registered only loS''. 



4. Two thermometers, one naked, the second wrapped in 

 dried silk, were fixed in a flisk as for la-t experiment, but a 

 little wa'er wa^ placed in the fla-k, which was then plunged into 

 hot water a; before. The naked thermometer rose rapidly at 

 first, but it was soon outstripped by the covered one. The fol- 

 lowivg was the result after s->me minute> : — Water, 128°; naked 

 thermometer, 118°; covered thermometer, 136°. 



5. Two thermometers, one naked, the sec md envelo.^ed in 

 dried silk, were passed through a cover fitting a glass vessel 

 which WIS carefully dried and heated, and the cover was 

 cemented on to prevent the )ias age of moisture from the air. 

 After an hour the naked thermometer had cooled to 81° (tem- 

 perature of air), and the covered one to 83°. They were then 

 changed to a similar vessel containing a little water ; the 



