244 



NA 1 URE 



Yjfan. 13, 1 88 1 



each CO ifine himself to his own branch, "at the sme time recog-a 

 ni'-ing the importance of our discovery ; and Herr Koni^, in 1 

 paper jiublislied in the Berkhte, xii. 97, referring to our fir.st 

 paper, says : " Es ist der erste gl.itte Ueber^ang der China- 

 allcaloide in eiue jedeafalls einfachere Substanz — das Pyridin. " 



William Kamsay 

 James J. Dobeie 

 Glasgow University 



The Temperature of the Breath 



Dk. Dudgeon's first letter under this hea ling contained tlie 

 suggestion of a friend that his enigmatical thermometric readnjgs 

 were to be accounted for by the high temperature "caused liy 

 the conden ation of the moisture of the breath by the silk hand- 

 kerchief." The discussion that followed has mt only brou.jh'; 

 ui back to this solution, but has also furnished us with an 

 authoritative expression of opinion that the clinical thermometer 

 is not sensitive to pre-sure. F. J. M. P. first hinted the 

 contrary proposition only to have it thrust aside by Dr. Dudgeon 

 with blunt denial, neglected by Dr. Roberts, and finally 

 discarded by himself for no other apparent reason than that 

 aqueous vapour in condensing liberates heat. Yet I venture to 

 as ert that readings as high as any obtainable by Dr. Dudge mi's 

 method, less the pressure, can be obtained by a very similar 

 mode of experimenting, without the developed heat: i. If the 

 bulb of a thermometer, protected by paper or other non- 

 conductor, be squeezed in an intermittent manner between finger 

 and thumb, it will be found that the mercury can readdy he 

 made to dance up and down through about a degree on the scale 

 with a celerity not attributaMe to changes of temperature. 2. If 

 eighteen inches of cotton thread Ije tightly wound about the 

 bull), on immersing the thermometer in water it will exaggerate 

 the temperature sometimes by as many as 12° F. 3. If a tube 

 filled with cacao butter be substi'uted for the thermometer the 

 butter bcLieath the thread will be longer in melting than that in 

 other portions of the tube, a result which I think proves that 

 the high readings of experiment No. 2 are not temperature, but 

 (iu thel'ght of No. i) pressure readings. 



My cliief object in writing is to protest on general grounds 

 again-t the treatment accorded to V. J. M. P.'s suggestion, b.it 

 at the same time I wish to express my opinion that Dr. Roberts' 

 argument would have been strengthened by giving heed to it, 

 for I see nothing in his aaoiint of the interrupted experiment not 

 explainable on the pressure hypothesis al me, the descending 

 series of readings b;ing perchance due to a yielding of the 

 wrappings under prolonged tension. On the other hand I have 

 to thank this omission on Dr. Roberts' part for having induced 

 me to test the subject for myself, and thus experience, m 

 re^«ating his experiment, the rare pl-asure of scientiiic ^urpri^e 

 at seeing the index mount higher and higher above the level of 

 my expectations under conditions which left no doubt as to the 

 cause being a rise of temperature. Dr. Dudgeon has done good 

 .service by directing attention to a simple experi'uent which, 

 properly interpreted, throws new light on the philosophy of 

 clothes, and j-hould prove a telling shaft in the quiver of popular 

 science. Wm. McLaurin 



Islington, December 26, iSSo 



In the number of Natitre which reached Madras after the 

 departure of the mail conveying my letter of the 9th in,t., I was 

 glad to read Dr. W, Roberts' abundantly full and lucid exphna- 

 tion of the heat produced by breathing on thermometers enveloped 

 in hygroscopic substances. He has, by a very simple method, 

 c onfirmed the view endorsed in my communication in Nature, 

 vjl. xxiii. p. 534. 



That the effects of friction and of c ompressi on of air are so 

 slight that they may be disregarded, has been proved ; and the 

 rise has been clearly traced to absorption of aqvieous vapcur. It 

 has yet to be determined how much of this heat may be accounted 

 for by the reduclioa of aqueous vapour to the fluid state, and 

 how much by capillary action and absor,.tion of water, with or 

 without chemical anion, and its reduction to the soli I state — all 

 of which may be included in hygroscopic action. This deter- 

 mination wou'd involve some intricate inve-tigations which some 

 scientific specialist may perhaps find leisure to undertake. That 

 more than simple vapour condensation is concerned in the pro- 

 duction of hygroscopic heat is shown by the ri e of temperatme 

 on ndding water to a non^saturated hygro c opic subst mce. 



A scientific colleague has .suggested to me that some cases of 

 very high axillary temperatures may be etplained by the clothing 

 of patients being pressed into the axilla in contact with the 

 thermometer. Thus, by folding a banian round a thermometer 

 placed in the axilla, I registered a temperature above 100° F., 

 while the tempera ure in the bare axilla was gS-j. It is evident 

 that recently changed and dri.-d clothing and cl jthing warmed 

 by the body of a non-perspiring fever patient would have still 

 more efiect when pre-sed clo ely into a hot and moist axilla. 

 Although this point is important mainly to physicians, I venture 

 to draw attention to it through your columns on account of its 

 connect! on with the subject of hygro copic heat. 



C. J. McNally 



Mad as, December 16, iSSo 



Distance of Clouds 



I HAVE conveniently determined the distance of passing clouds 

 by a method probably not new, but which I have not seen 

 described. 



It consists in ascertaining the velocity with which the shadow 

 of a cloud traverses level ground, which is easily observed, and 

 of coarse giv.s the velocity of the cloud itself. 



The angular motion per second of clouds passing overhead is 

 simultaneously observed by means of a coarse micrometer in a 

 telescope, or with a theodolite. 



The distance is thus obtained with fair approximation. 



Distance = ^ — 34J_^ ^ being the velocity in feet per second, 



and K the number of minutes of arc described in / seconds. 



A distant mirror may be advantageously used in determining 

 the velocity of the shadow. 



Edwin Clark 



Fluke in Calves 



Can any of your readers account for the following facts? — 

 An examination of the liver of some .six-weeks-old calves which 

 had never touched any food but their mother's milk showed 

 then to be infested with fully-developed Fluke [Dlstomi 

 hcpatica). It is clear that the presence of these flukes does not 

 admit of the usual explanation, viz., the ingestion with green 

 food or water of mollusca bearing the larva in one of its earlier 

 stages. 



I sh ould be gi-ateful if any of your readers could suggest an 

 explanation of the mole in which the fluke entered the liver of 

 the calf. Is it possible that the larva may h ive passed into the 

 milk of the mother, and so have entered the stomich of the calf? 



It may interest some of your realers to know that traces of 

 fluke were present in the livers of cattle lately killed wh':n in 

 high condition. The flake had apparently been established in 

 the liver some considerable time previous to the slaughter of the 

 animds, and bad per. shed on their attaining to a stile of high 

 health and vigour. A. B. 



JOHN STENHOUSE, LL.D., F.R.S. 



IN the early morning of the last day of the old year we 

 lost one of the few surviving founders of the Chemical 

 Society, Dr. John Stenhotise. He was born at Glasgow, 

 October 21, 1809, the son of William Stenhouse of the 

 well-known firm of calico-printers, John Stenhouse and 

 Co. of Barrhead. He was educated first at the Grammar 

 School and then at the University of Glasgow, anJ long 

 resided in his native city. At an early age he turned his 

 attention to chemistry, and diligently studied that science 

 under Graham and Thomson, and subsequently with 

 Liebig at the University of Giessen. When he removed 

 to London, after the failure of the Western Ban'.c of 

 Scotland had deprived him of the fortune bsqueathed to 

 him by his father, he became Lecturer on Chemistry in 

 St. Bartholomew's Hospital, London, but was obliged to 

 resign that appointment in 1857 owing to a severe attack 

 of paralysis. Even this affliction however did not dis- 

 courage him, and after the lapse of a short time he 

 renewed his scientific labours. In 1865 he succeeded Dr. 



