AGRICULTURAL METEOROLOGY. 121 
to have more certain and abundant harvests, and I therefore think a more extended 
network of observation in the several States than that carried out by the Secretary of 
War for the benefit of commerce is desirable for agriculture, and that these should be 
subordinated to a central office or bureau, in order to make them uniform and utiliza- 
ble. I have only partially succeeded in impressing this view upon Congress. I have 
no contrel over the various colleges alluded to, and the adoption of this plan would 
involve some additional expense in each institution, and, therefore, I am unwilling to 
assume the position of adviser, although I am of the decided opinion that the pursuit 
.of such inquiries is a part of the plan of improvement in agriculture which it was con- 
templated these institutions might effect. 
INSTRUCTIONS FOR THE OBSERVATION OF PERIODICAL PHENOMENA. 
The name of pericdical phenomena has been applied, by Quetelet, to 
a diversity of physiological functions or habits of plants, animals, and 
man. While the earth performs its daily and annual revolutions, a 
series of phenomena are unfolded upon its surface which the periodical 
return of the days and seasons brings regularly back in the same order. 
The phases of the existence of the minutest plant-louse are intimately 
bound up with the phases of the existence of the plant that nourishes 
it; and this plant itself, in its gradual development, is the product of 
all the anterior modifications of the soil and atmosphere. 
The study of these periodical phenomena, of the highest importance 
in agriculture, has engaged the attention of observers in all times, from 
the Greek philosopher, Theophrastus,* down to the great naturalist, 
Linneus,t who, more than a century ago, first attempted a series of ob- 
servations on the flowering period of different species of plants. These 
observations, addressed to husbandmen, were published during the 
years 1750-1-2, under the title of “‘ Calendar of Flora.” 
But this important study was almost abandoned for want of aregular 
system of investigation, until 1839, when Quetelet began, at the garden 
of the observatory of Brussels, the first regular series of observations 
on the period of flowering.t In 1841 these observations were carried 
on in several parts of Belgium. In 1842~’43 they were improved and 
extended to other nations. In 1842 Quetelet published his “ Instruc- 
tions§ for the Study of Periodical Phenomena,” both in plants and ani- 
mals; while Schwann|| added his own “ Instructions Applied to Man.” 
Quetelei’s “ Instructions” were translated into English in 1845, and re- 
vised and enlarged by a committee appointed by the British Associa- 
tion for the Advancement of Science ; 4] they were also translated into 
German by Ch. Ritter and Mchlmann, and recommended to observers 
in Germany. 
Finally, in the International Congress of Statistics, held at Vienna, in 
1857, it was resolved to form a general outline for the observation of 
periodical phenomena at large, and submit it to the next Congress at 
London. Quetelet, director of the observatory at Brussels, and Karl 
Fritsch, assistant at the observatory of Vienna, were instructed to draw 
up the outline. The “Instructions,” written and published in 1859, by 
Fritsch,** were submitted to the Congress held at London from the 16th 
to the 21st of July, 1860. ; 
* Libros VI, de causis plantarum, conjuncta opera D. H. F. Linkii, excerpta solus ex- 
plicare conatus est J. C. Schneider, Lipsiz, 1818, 5 vol., 8vo. 
t Ameenitates Academic, seu dissertationes varie physicm, medice, botanic, Ludg. 
Batav. 1749~69. 10 vol. 8vo, Td. Erlang, 1785~90. 
¢ Memoires de Académie des Sciences de Bruxelles, 1841, vol. xiv, pp. 3-5, 19-28. 
§ Bulletin de l’Académie des Sciences de Bruxelles, 1842, vol. ix. pp. 65-95. 
| Bulletin de ’Académie des Sciences de Bruxelles, 1842 vol. ix. 2d part, p. 120. 
{i Report of the British Association, 1845, pp. 321-336. 
eee eesbenichte der Wiener Akademie der Wissenschaften, 1859, vol. xxxvii, pp 
