298 THROUGH THE FIELDS WITH LINN&US 



The periods do not seem to be always so regular as 

 Linnaeus marked them at Upsala. Plants which expand 

 their flowers in the evening, as some species of Hesperis, 

 Pelargonium, &c., were called by Linnasus Plantce ti istea 

 on that account. 1 



Mitchell writes (September 1 748) : ' We are anxious 

 to see a fuller exposition of your botanical clock, which 

 cannot but be curious and useful.' 



1748. Collinson, who always kept Linnaeus in order, 

 and told him home truths, writes : ' But pray con- 

 sider what will become of the clockmakers if you can 

 find out vegetable dials. Next, I am afraid you will be 

 spoiled for a gardener, you will grow so rich with the 

 breeding of Oriental pearls.' 



Linnaeus was always carrying on experiments ; but 

 not till 1762 did he make any money by his discovery of 

 the way to breed pearls in the river Mussel, when the 

 Diet 2 gave him upwards of 52 OL sterling for what seems 

 to have been the least valuable of his discoveries the 

 artificial generation of pearls within their shells. They 

 are pearls certainly, but knobs of chalk would be nearly 

 as beautiful. 



More important than these things was the rural 

 calendar he formed for the regulation of the labours of 

 husbandry, according to the appearance of plants at stated 

 intervals. 3 This marks the months the flowers appear in. 

 Linnaeus kept many climatic registers. The maximum 



1 Balfour. 2 Stoever. 



3 Calendarium Florfe, edited by Berger of Upsal, date 1756. 



