[Vou T., Ho. lU :
���regulariU" in observing the stars of the ' Ameri- can ephemeria,' the sun, moon, anil planets, and Itets of miscellaneous object* chiefly used by exploration parties and expeditions in determining latitudes. In the choice of dates when observations of the bodies of the solar system, particulftrlj the outer great plnnets. were made, no systematized plan of opei-a- tion appears to have been followed. It would be well if the adnptation of the obaervaliona to the problems of the future investigator were kept in mind equally prominently with the fact that these bodies, a month or two preced- ing the opposition -time, transit the meridian at inconvenient hours beyond midnight. The days of observation slionid be so chosen that it will be possible to derive a series of normal places for each planet symmetrically placed with reference to the eix)(;h of least distance from the earth.
The great equatorial, with Professors Hall and Holden as observers, was mainly occupied with work upon double stars ; but the satellites of the outer planets were fully observed, as also the great nebula of Orion, the observa- tions on which were i)ublished by Professor Holden several years ago, in his well-known mont^aph.
There is no record of observations with either the prime vertical transit, the mural circle, or the east transit instrument ; and there is very little to show for the lesser equatorial of the observatory. The meteorological observations have been conducted on obout the same plan for a long scries of years, having been begun long before the Army signal- service was in successful operation as a meteorolc^ical bu- reau. If they are continued on the supposition that they form a valuable addition to meteor- ology, this would appear to be an insufficient reason ; while, for any known practical bearing on astronomy, they arc barely worth the making and printing.
The volume of observations for the year 1879 concludes with two api>endixes, the lat- ter of which is a detcrmiuatiou of the semi- diameter of the moon from occultations of the Pleiades, by Mr. H. M. Paul ; and the former, by Professor Hall, on the parallax of a Lyrae and 61 Cygni, In the appendix to the volume for 1«80, Mr. Winlock has so collected all the observations and drawings of the great comet of 1S82, made at the naval observatory, as to make them available, in couslderable part, for definitive discussion of the comet's orbit.
While, on looking casually through these volumes, one is impressed with the necessity of bestowing greater care on the details of
��proof-reading, it is a pleasure to note the sud
den influx of new tyi>e8 in the printer's fonta^^; from which the latter part of the \olume foi— 1880 was set, replacing the old types, whicl^^ liad become so much worn as to make score^B- of figures on many pages quite indecipherable- With the commencement of the present year_, the observatory, under the superintendency oC~ Rear-Adrairal Franklin, has begun the execu- tion of a pro-oi^anized plan of astronomical work. This has already been printed and dis- tributed, and the advantages to be expected from this arrangement will be watched for witll_ much interest.
��BRA IN-EXHA US TION.
��Thiih book belongs to a class which finds circulation only in this country, and is not calculated to establish a foreign reputation for the author. If the time spent upon its prep- aration had been given to accurate observation or careful experiment, and the results con- densed into an article of twenty pages, the author might have secureti some attention. The work consists of a mass of theoretical statements regarding normal and abnormal Itra in -action, few of which have any basis in ascertained facts. We know that brain-ex- haustion is ])ossible. and we know nnder what conditions it occurs. The chapter on causa- tion contains a fair summary of these condi- tions. We do not know the meclianism of its occurrence, and we cannot atlirm, in n glvei case, that a definite line of treatment succeed.
The author has a favorite method which is the object of the book to urge. method does not cotnmend itself to those who' are familiar with recent German investiga- tions by experiment, which, as far as animals go, are directly opposed in their results to the conclusions reached by Dr. Corning. Electri- cal treatment of brain-disease must be con- ducted with caution, and only with the aid of an accurate galvanometer which measures the intensity of the current, and enables the phy- sician to know at any moment what strength he is using. Of this, as well as of other necessary precautions. Dr. Corning seems unaware, forj he recommends the use of from ■ five to fif cells,' a wholly unknown quantity.
Science demands facts, not theories ; the sooner this is understood by tboBe seek a place injte ranks, the better.
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