president's address. 
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a scent of‘ Hyacinths at night, the Honeysuckle, the Dame’s Violet, 
and many of the Stocks. 
The paraffins give their name to a group of scents among which 
the Rose scent is the chief in importance, anil in which are included 
the honey scents, as those of the blossoms of Cherry, Plum, and 
Clover; the honey scent is found in combination with many in the 
preceding group, hence a great variety of odours. Among the 
Roses we have many different perfumes, and though there is no 
scent of tea in the so-called Tea Roses, as has been pointed out by 
the Rev. A. Foster-Melliar in the Book of the Rose, yet there are 
to be found the Clove scent in Safrano, that of the Raspberry in 
Mareehal Niel, of the Apricot in the Macartney Rose, and Mignonette 
in the Dog Rose, while a few Roses are absolutely scentless. 
Rosa rent if alia , from which, with its descendants, attar of Roses is 
chiefly made, may be considered to possess the typical rose scent. 
The last group consists of scents produced from ethereal oils, 
called terpenes, which scents are more often found in the stem and 
foliage than in the flowers. Lavender, Thyme, and Citron may be 
taken as examples. It is to be hoped that, in the near future, more 
attention may be given to this classification of vegetable perfumes. 
Another subject for enquiry is the fluctuating character of many 
of these scents. Why are some plants scentless at certain hours 
of the day and odoriferous at others ? The advantages to the 
plant of such an arrangement are patent, the periods of fragrance 
coinciding with the hours at which those insects are on the wing 
whose visits benefit the plants. Thus Acacias, which are visited bv 
Bees, are scentless in the evening; while flowers which attract 
crepuscular Moths are inodorous in the day-time; for the visits of 
insects which do not assist in the transference of pollen are 
disadvantageous to the plant. 
Very little appears to be known of the manner in which this 
intermittent emission of scent is brought about. Alternations of 
gentle rain with intervals of sunshine favour the promulgation of 
odours, the secretion of which is assisted by heat, and the increase 
or diminution of heat may often determine these periods of fragrance ; 
an increase helping to volatilize scent, and a decrease preventing its 
