TRANSACTIONS OF SECTION A. 771 



Did not Kepler ask : ' How many would be able to make astronomy their 

 business if men did not cherish the hope of reading the future in the skies ? ' And 

 did he not warn those who objected to the degradation of mingling astrology 

 with astronomy to beware of ' tluowing away the child with the dirty water of 

 its bath ? ' Even now, may we not consider all the astronomical research work 

 done at the Royal Observator}', Greenwich, as a by-product, since the Observatory 

 is officially maintained merely for the purposes of navigation ? And are there 

 not many of us who feel assured that, since researches in pure physics and the 

 elucidation of new physical facts must quite legitimately spring from routine 

 standardising work, the most direct way — even now at the end of the nineteenth 

 century — of securing for the country a National Physical Laboratory is to speed 

 forward a Government Standardising Institute ? 



Lastly, as you will find in Dr. Thorpe's fascinating ' Life of Davy,' it was the 

 attempt to discover the medicinal eflect of gases at the Pneumatic Institution in 

 this city that opened up to Davy the charm of scientific research. And, indeed, 

 the lloyal Institution itself, the scientific home of Davy, Faraday, Tyndall, 

 Rayleigh, and Dewar, owes its origin to Romford's proposal * for forming in 

 liondon by private subscription an establishment for feeding the poor and giving 

 them useful employment . . . connected with an institution for introducing and 

 bringing forward into general use new inventions and improvements by which 

 domestic comfort and economy may be promoted.' 



Coming now to physics proper, there is one branch which, although of deep 

 interest, has hitherto been much neglected. We possess three senses which 

 enable us to detect the presence of things at a distance — viz., seeing, hearing, and 

 smelling. The first two are highly cultivated in man, and, probably for that 

 reason, the laws of the propagation of the disturbances which affect the eyes and 

 the ears have been the subject of much investigation, whereas, although to many 

 animals the sense of smell is of far greater importance than those of seeing or 

 hearing, and although, even in the human brain, a whole segment — a small one in 

 modern man, it is true — is devoted to the olfactory fibres, the laws of the production 

 and propagation of smell have received practically no attention from the physicist. 

 For some time past it has, therefore, seemed to me to be of theoretical and practical 

 importance to examine more fully into the physics of smell. Various other occupa- 

 tionshave hitherto prevented my advancing much beyond the threshold of the subject, 

 but, as it seems to me to open up what is practically a new field of inquiry for the 

 physicist, I take this opportunity of putting on record some facts that have been 

 already elucidated. 



Various odoriferous substances have been employed in the experiments, and 

 for several of these I am indebted to Mr. W. J. Pope. Although the physicist 

 has been allowing the mechanical side of the subject to lie dormant, the chemist, 

 I find, has been analysing flowers and other bodies used in the manufacture of 

 scents, and then synthetically preparing the odoriferous constituents. In this way, 

 Mr. Pope informs me, there has been added to the list of manufactured articles, 

 during the past seven years or so, vanilin, heliotropin, artificial musk, irone and 

 ionone, which give the perfume of the violet ; citral, that of lemongrass ; coumarin, 

 that of hay, and various others ; and he has kindly furnished me with specimens of 

 several of these artificial scents, together with other strongly-smelling substances. 



If it be a proof of civilisation to retain but a remnant of a sense which is so 

 keen in many types of dogs, then I may pride myself on having reached a very 

 high state of civilisation. But with tlie present investigation in view this pride 

 has been of a very empty character, since I have been compelled to reject my own 

 nose as quite lacking the sensitiveness that should characterise a philosophical 

 measuring instrument. The ladies of my family, on the contrary, possess a nasal 

 quickness which formerly seemed to me to be rather of the nature of a defect, 

 since, at any rate in towns, there are so many more disagreeable odours than 

 attractive ones. But on the present occasion their power of detecting slight smells, 

 and the repugnance which they show in the case of so many of them, have stood 



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