SCIENCE. 
167 
in conjunction with the negative or lower end of the needle. 
This is continued from high to low and from low to high 
water and from day to day, the result being recorded as 
read oft'. The mechanical difficulties in the construction of 
the machine are very great, but not considered insuperable. 
ON THE DEFICIENCIES OF METEOROLOGICAL 
WORK IN DATA OF VALUE TO AGRICUL- 
TURE. AND MEANS FOR SUPPLYING THEM. 
By William McMurtrie. 
Meteorological records, as they are and have been and 
are being made, are deficient in many of those data which 
have the most important influence upon farm crops. Tem- 
peratures are recorded, but they are always observed in the 
shade. Rainfall is given, but often in such a way as to ren- 
der its record of no value in the study of the development 
and condition of crops, because no indication is given as to 
the way in which it is distributed ; light being of little im- 
portance to meteorologists generally, while it is one of the 
most potent factors in the development of vegetable and 
animal life, has been almost completely ignored. Late in- 
vestigations have proven conclusively the importance of the 
tension of atmospheric electricity upon vegetation, and it 
should be regularly observed and recorded. In fact, me- 
teorologists have principally confined themselves to the re- 
cord and study of such conditions as enable them to predict 
the approach and occurrence of storms, thus looking more 
to the commercial than to the cultural side. Gasparin was 
the first to call attention to the importance of the relations 
of Meteorology to agriculture, and he has had at least two 
active followers — Quetelet in Belgium, and Marie Davy in 
France. Through the instrumentality of the latter there 
has been established, near Paris, an observatory of Agricul- 
tural Meteorology, where observation and record of all the 
conditions above named is made. The results already ob- 
tained have shown great practical value, and worthy of the 
means and labor required in securing them. In this coun- 
try we have nothing similar to it. Our Signal Bureau, as 
nearly perfect as may be for the purposes for which it was 
designed, is devoted to the record and study of those ob- 
servations as wiil render possible the prediction of future 
conditions which may affect human affairs, than such as may 
influence the development of crops. Besides this, the num- 
ber of stations at which observations are made in this coun- 
try is too limited, being not over 800, while for agricultural 
work 3, coo would not be excessive. Additional work 
should, therefore, be carried on, and observations at a larger 
number of stations made and recorded, to be discussed in 
connection with the records of observations made upon the 
condition of the crops. The nature of the work is such that 
it should be undertaken by the Department of Agriculture, 
and the organization of the latter with the 2,300 reporters it 
already employed would be well adapted to it. Fortunate- 
ly, General Le Due, the Commissioner of agriculture, is in 
favor of the establishment of such work in the Department, 
but will require congressional support to enable him to do 
so. The plan of work suggested by the author is as follows : 
1. The establishment of a system of observation and record 
among the reporters of the Department of Agriculture, and 
others whose co-operation could be secured throughout the 
United States and Territories, with instructions to observ- 
ers to keep careful records of the conditions of atmospheric 
pressure, temperature in its various relations, relative hu- 
midity, evaporation of moisture, winds, light, tension of 
atmospheric electricity, occurrence of dews, fogs and frosts, 
and report them at stated intervals of time to the Depart- 
ment for consideration and permanent record. I. The col- 
lection of meteorological records from every part of the 
world, from which to construct detailed tables showing the 
relations of all the conditions named above, and may influ- 
ence the growth and health of vegetation. 3. The construc- 
tion of maps showing the geographical distribution of crops, 
to be used in connection with the meteorological or climatic 
data to be collected. 
PRELIMINARY ACCOUNT OF A SPECULATIVE 
AND PRACTICAL SEARCH FOR A TRANS- 
NEPTUNIAN PLANET. 
By D. P. Todd, M. A., Assistant in the Office of the American 
Ephemeris and Nautical Almanac. 
So early as the year 1834, Hansen was credited with ex- 
pression of the opinion, in correspondence with the elder 
Bouvard, that a single exterior planet would not account 
for the differences between the tabular and observed longi- 
tudes of the planet Uranus. Dr. Gould, however, in his 
“ Report on the History of the Discoveryof Neptune,” says: 
“ I have the authority of that eminent astromener himself 
(Hansen) for stating, that the assertion must have been found- 
ed on some misapprehension, as he is confident of never 
having expressed or entertained that belief.” 
Professor Peirce’s criticism of the investigations of Le 
Verrier, to the effect that his predicted orbit of Neptune 
was so widely discordant from its observed orbit as to in- 
dicate that his computations did not pertain to the actual 
disturbing planet, elicited from him the reply that the per- 
turbations of Uranus due to a possible planet exterior to 
Neptune might readily cause an uncertainty of 5" to 7 in 
the fundamental data of his research. 
In 1866, the Smithsonian Institution published the gen- 
eral tables of Neptune, by Professor Newcomb. In the in- 
vestigation of its orbit the author proposed: “ 3. To inquire 
whether those motions [of Neptune] indicate the action of 
an extra-Neptunian planet, or throw any - light on the ques- 
tion of the existence of such a planet.” He concludes 
(page 73) that it is “almost vain to hope for the detection 
of an extra-Neptunian planet from the motions of Neptune 
before ihe close of the present century.” 
In 1873, the Smithsonian Institution published the gen- 
eral tables of Uranus, by Professor Newcomb. His suc- 
cess in the treatment of the theory of Uranus was such that 
astronomers generally may be said to have been satisfied 
from the smallness of the longitude-residuals, that there 
existed no evidence of perturbative action upon Uranus 
other than that actually taken into account in the construc- 
tion of the tables. It is well known, however, that since 
the publication of these tables the error of longitude has 
been increasing. 
Sometime in the spring of 1874, the first preliminary out- 
line of the very r simple method which I have here employed 
in the treatment of planetary residuals with reference to ex- 
terior perturbation, suggested itself to me. For more than 
three years very little opportunity offered for consideration 
of the problem of a trans-Neptunian planet. In August, 
1877, however, I began to devote the larger portion of my 
leisure time to the theoretic side of the question. It was 
soon evident that no certain hold upon any' possible cause 
of exterior perturbation could be obtained from the resi- 
duals of Newcomb’s tables. And I may' remark here that I 
have consequently chosen the term speculative rather than 
theoretic as applying more fitly to the investigation which 
preceded the actual telescopic search. 
It did not seem to me that the magnificent researches of 
Le Verrier and Adams on the perturbations of Uranus 
should be taken as models in the present investigations, 
for two reasons : 
(1) The residuals of longitude which must form the basis 
of the investigation are not sufficiently well marked to jus- 
tify the execution of so laborious a research, especially' if 
it be found that a simple, rational treatment, unencumbered 
with the refinements of analysis, may be fairly interpreted 
as indicating the position of an exterior perturbing body 
with merely a rough approximation. 
(2) Even in the case of Uranus, and the theoretic search 
for Neptune, where the residuals of longitude were very 
strongly marked, many' of the elements pertaining to 
the disturbing planet, which Adams and Le Verrier sought 
to determine theoretically', turned out afterward, when their 
real values became known, to have been indicated with only' 
meagre precision. Much less should we now expect these 
elements to be given with any' certainty in the case of a 
planet exterior to Venus. 
This provisional treatment of the residuals of Uranus 
was undertaken, then, as a preliminary to the proposed 
