44 REPORT OF THE SECRETARY. 
indicated in regard to storms, by the investigations of Mr. Espy and 
others, in relation to the United States, namely, that all such meteoro- 
logical phenomena, as variations in the pressure of the atmosphere, 
sudden changes of temperature, either of unusually warm or cold 
weather, thunder-storms, tornadoes, as well as storms of wind, rain, 
&c., which occur within the temperate zones, travel from west to east. 
The simultaneous system of observations established by the Institu- 
tion furnished the means of placing this great law of meteorology in 
prominent relief, and of first reducing it to practical utility. 
As early as 1849 the Institution organized a system of telegraphic 
despatches, by which information was received at Washington of the 
condition of the weather at distant places in the southwest and north- 
west, and from this, in accordance with the law before mentioned, 
it was often enabled to predict, sometimes a day or two in advance, 
the approach of any larger disturbances of the atmosphere. Subse- 
quently the telegraphic despatches were daily exhibited at the 
Institution on a map of the United States by means of a series of 
movable cards of different colors, which indicated the meteorological 
condition at various points, showing at a glance in what parts of the 
country it might be clear or cloudy, raining or snowing; and by 
arrows the existing direction of the wind. The returns were also 
published in one of the evening papers. Unfortunately this enter- 
prise was interrupted by the cessation of the observations in the 
southwest, and by the constant use of the telegraph for the purposes 
of the government. 
The advantages possessed by the Smithsonian Institution for inves- 
tigations of this kind will be evident, when it is recollected that a 
large portion of its observers are stationed west of Washington, that 
the phenomena approach it over a large extent of land, and can be 
critically noted through every part of their passage eastward, while 
the phenomena which are presented to the meteorologists of Hurope 
traverse in reaching them a wide expanse of ocean, from which only 
casual observations can be gleaned. 
The publications of the Institution contain many memoirs which 
have tended to advance the science of meteorology. Among these 
may be mentioned the meteorological and physical tables prepared 
at the expense of the Institution by Professor Guyot, and filling a 
large octavo volume of the Miscellaneous Collections. No work extant 
answers the same purpose with the one referred to, which has hence 
become a general standard of reference, the constant demand for it 
