General Remark.-The climatic feature of predominant interest in California lies in the rains of winter, which, although they fell in the early part of the present season in ample abundance for agricultural purposes, nevertheless, in their subsequent diminution, confirm the opinion expressed by us in former remarks, that the cultivator of the earth cannot depend with any certainty upon them alone, but must be prepared to supply their deficiency, whenever it occurs, by irrigation-for which expedient no other country, perhaps, is better adapted, both as regards soil and climate, as well as facilities of commanding water.

2. Daylight Meteor of Nov. 15th, 1859.-Of this remarkable body Professor Loomis has already published an interesting account at p. 137 and 298 of this volume. The meteor being one of the most brilliant on record deserves the fullest possible investigation, and we are glad to find in the Journal of the Franklin Institute of Philadelphia, for March and April, a valuable paper thereon by Mr. Benj. V. Marsh of that city, giving an extensive series of observations which he has collected, together with his deductions therefrom.

The meteor was seen in full sunshine, as a large ball of fire, from Salem, Mass., to Petersburg, Va. Its path was probably inclined to the vertical about 35°, and the direction of its motion was nearly west. Its velocity was very great, perhaps full 30 miles per second, and the meteor appears to have become luminous when more than 100 miles above the earth. During its brief passage of two or three seconds, it exploded several times, with reports which were loud and violent. These reports or detonations made two series, the whole occupying only half a second of time, the individual sounds being distinguishable because of the different distances they had to travel to reach the ear. The column of smoke resulting from the explosions was nearly a thousand feet in diameter, and its base was vertical about four miles north of Dennisville, N. J. The immense volume of smoke or substance of the meteor, dissipated by its excessive heat, shows that the body was of very considerable magnitude. The meteor's path would strike the earth near Hughesville, on the northwestern boundary of Cape May County, N. J., in which vicinity, or a few miles further west, it is probable that fragments may yet be found. Will nobody look for them?

V. MISCELLANEOUS SCIENTIFIC INTELLIGENCE.

1. Probable Origin of Flint Nodules in Chalk.-DR. G. C. Wallich, Surgeon in the Indian army, has published (in the Quart. Jour. Microscopical Sci., No. xxx, p. 36) an interesting paper on the siliceous organisms found in the digestive cavities of Salpa-embracing under this head the whole molluscoid tribes that frequent the open sea in shoals and live upon the microscopic organisms it contains. These creatures are in their turn the food of whales. In the digestive cavities of the Salpæ the siliceous shields of Diatomaceæ, &c., are freed of all or nearly all their soft portions, and these minute organisms aggregate into masses which in the whales are further aggregated and in the form of coprolites fall in vast numbers upon the pulpy cretaceous strata of Foraminiferæ, &c., now known to form the bottom of the ocean in many places, imbedding themselves there as nodules similar to, certainly, if not identical with, the flint nodules in the Chalk.

2. New form of Compressor for use with the Microscope, (in a letter to Prof. G. C. SCHEFFER).-My Dear Sir,-At your request I enclose a sketch of the little instrument that I use as a substitute for the ordinary compressor, in mounting objects for the microscope.

The frame a, is made from one piece of hard brass, possess

ing

sufficient

elasticity for the purpose,-held in place and adjusted by the milled nut on the screw b. This screw is

firmly riveted

in the frame at a, and plays freely in a slot at b. The swinging tripod, (also cut from one piece,) is loosely riveted to the bent end of the frame as shown in section at f, having sufficient play in the collar to adjust itself to any inequality in the slide or the cover.

The centre of the frame, at c, under the tripod, is pierced with a hole of sufficient size to see the object to be mounted, so that the pressure from the screw can be adjusted without injury to the object. shows a slide, d, and cover, e, in place.

The sketch

For mounting objects dry, or for covering cells I find it useful as it enables me to hold the cover securely while I have access to its entire edge, and can turn it in every direction to apply the cement. For mounting objects in balsam which require very thin covers, say '01 to 005 of an inch, such as the silicious epidermis of plants and other test objects, I add to the pierced hole in the frame a circular shield of glass, a little less in diameter than the cover, and of the thickness of an ordinary slide, imbedding but a small portion of its thickness in the brass. Then, after placing the cover on the balsam, and spreading it by heat, I put the slide cover down in the frame, and apply a pressure to drive off the superfluous balsam. The raised surface of the glass shield, keeps the exuding balsam from the frame, and at the same time prevents any bulging of the thin glass at the centre. Dried in this way, under pressure, it is easily taken from the frame and cleaned. I have found it a very simple and satisfactory way of perfecting the mounting of difficult test objects.

Other modifications of this little instrument will readily sugest themselves to you. It is, to me, a great convenience to have a dozen of them at hand, of various sizes, as I can thus get my slides thoroughly seasoned under a perfectly uniform pressure-and I can have twenty of them made for the cost of one English compressor.

My friend, Mr. McAllister, Optician, 728 Chestnut St., Philadelphia, made them for me from a drawing, very neatly and accurately, at seven dollars and fifty cents per dozen ($7,5%).

Very truly, your friend,

Washington, Jan. 4th, 1860.

S. MORTON CLARK.

3. On Contraction of the Muscles, induced by Contact with Bodies in Vibration; by O. N. ROOD, Professor of Chemistry in Troy University.— Some time since, when grinding a slide for microscopic purposes, as the strip from time to time accidentally came into vibration, I experienced, in the hand holding it, a numbness, and, at times, an absolute inability to relax the grasp. It seemed as though an involuntary contraction of the muscles had been effected by the vibratory action.

For the examination of this matter, the apparatus seen in the woodcut

was devised: b is made to revolve at a rate of from 50 to 60 revolutions per second; rr is a rod of iron placed excentrically and so that the distance ra is equal to 4th of an inch. To protect the hand

from blisters, the brass tube t encloses the rod, fitting it very loosely. When the hand is laid on this sheath, the rate of rotation being between 40 and 60 revolutions per second, a feeling of numbness is first perceived; the muscles involuntarily contract with considerable force, and the hand grasps the sheath tightly. As long as this rate of revolu tion is kept up, it is almost impossible, by an effort of the will, to relax the grasp, just as is the case with the electro-magnetic machine employed for medical purposes. The sensations, indeed, resemble those occasioned by the use of this apparatus, and usually extended as high as the elbows. At the termination of these experiments no particular inconvenience was experienced, although the sensations produced by the higher rates of vibration were painful.

Experiments were made on different parts of the arm and hand. Tho results obtained differed in degree rather than in kind.

The resemblance of the symptoms and sensations produced by electricity and mechanical vibration, is at least singular, and may eventually throw some light on the method in which electricity causes contractions in the muscles.

Troy University, Feb. 3d, 1860.

4. Large Object-Glass.-Messrs. Alvan Clark & Sons, of Boston, have completed on their own account, an object-glass with a focal distance of sixteen feet, and clear aperture of twelve inches. It has a nice defining power, and Mimas, the nearer satellite of Saturn, was seen with it Feb. 14th and March 2d and 4th.

5. Boyden Premium.—URIAH A. BOYDEN, Esq., of Boston, Mass., has deposited with the Franklin Institute, Philad., the sum of one thousand dollars, to be awarded as a Premium to "any resident of North America, who shall determine by experiment whether all rays of light, and other physical rays, are, or are not transmitted with the same velocity."

The conditions are given in an advertisement at the end of this Number. 6. Geological Survey of California.-We learn that a bill for securing the geological survey of California is now under consideration and if not so already, is likely soon to become a Law. So important an act must meet with the approval of every one interested in the material prosperity of the golden state: while science has much to expect every way from the proper discharge of such a commission.

SECOND SERIES, VOL. XXIX, No. 87.-MAY, 1860.

BOOK NOTICES.

7. Elements of Chemical Physics; by JOSIAH P. COOKE, Jr., Erving Professor of Chemistry and Mineralogy in Harvard University. 8vo. pp. 739. Boston, Little, Brown and Company, 1860.-We cannot state the nature and scope of this important contribution to our scientific literature better than by quoting the following paragraphs from the Author's preface.

"The history of Chemistry as an exact science may be said to date from Lavoisier, who first used the balance in investigating chemical phenomena, and the progress of the science since his time has been owing, in a great measure, to the improvements which have been made in the processes of weighing and measuring small quantities of matter. These processes are now the chief instruments in the hands of the chemical investigator, and it is evidently essential that he should be familiar with the causes of error to which they are liable, and should be able to determine the degree of accuracy of which they are capable. All this, however, requires a theoretical knowledge of the principles which the processes involve, and a chemical investigator who, without it, relies on mere empirical rules, will be exposed to constant error. This volume is intended to furnish a full development of these principles, and it is hoped that it will serve to advance the study of chemistry in the colleges of this country. In order to adapt the work to the purposes of instruction, it has been prepared on a strictly inductive method throughout; and a student who has acquired an elementary knowledge of mathematics will be able to follow the course of reasoning without difficulty. So much of the subject-matter of mechanics has been given at the beginning of this volume as was necessary to secure this object; and for the same reason, each chapter is followed by a large number of problems, which are calculated, not only to test the knowledge of the student, but also to extend and apply the principles discussed in the work. Regarding a knowledge of methods and principles as the primary object in a course of scientific instruction, the author has developed several of the subjects to a greater extent than is usual in elementary works, solely for the purpose of illustrating the processes and the logic of physical research. Thus, the means of measuring temperature and the defects of the mercurial thermometer have been described at length, in order to show how rapidly the difficulties multiply when we attempt to push scientific observations beyond a limited degree of accuracy; so also the history of Mariotte's law has been given in detail, for the purpose of illustrating the nature of a physical law, and the limitations to which all laws are more or less liable; the condition of salts when in solution, and the nature of supersaturated solutions, have in like manner been fully discussed as examples of scientific theories; and, lastly, the method of representing physical phenomena by empirical formulas and curves, which are the preliminary substitutes for laws, has been illustrated in connection with Regnault's experiments on the tension of aqueous vapor."

After advising the student to study the details of science from original memoirs rather than from digests, and enumerating the chief sources from which he has drawn his facts and illustrations, the Author announces his design of following the present volume with two others.

Although the present volume is a complete treatise in itself of the principles involved in the processes of weighing and measuring, it is also intended as the first volume of an extended work on the Philosophy of Chemistry. The arrangement of the chapters and sections has been adopted with this view, and the inductive method begun in this volume will be extended through the whole work. The second volume will treat of the theory of Light in its relation to Crystallography (including Mathematical Crystallography), and also of

Electricity in its relations to Chemistry. The third and last volume will be on Stoichiometry and the principles of Chemical Classification. This volume is now in preparation, and will be published next."

We have read, or studied, the larger portion of Prof. Cooke's present volume, with care, and, are happy to add, with much satisfaction. It is a more elaborate and thorough discussion of the subjects on which it treats than has before appeared in any text-book. All the important propositions are mathematically demonstrated in a simple but thorough manner. The volume demands and must receive exact and searching study, and any chemical teacher who intends to employ it as his class book will find it capable of the same treatment which he has been accustomed to regard as peculiar to mathematical text-books. The French units of weight and measure are employed exclusively, and a collection of tables (21 in number) is added for scientific reference and for the convenience of the student and teacher in solving the problems (420 in number) which are appended at the close of each principal subdivision of the subject. The whole subject matter of the volume is treated under five chapters, viz., I. Introduction, II. General Properties of Matter, III. The Three States of Matter, IV. Heat, and, V. Weighing and Measuring.

The mechanical execution of the work is beautiful, and the press seems to have been very carefully supervised.

One circumstance in connection with this work cannot fail to attract the attention of all teachers of Chemistry in American Colleges, namely, that a revision of our whole scientific curriculum is demanded in most of our higher Institutions in order to admit of the expansion demanded by the introduction of such a treatise as Cooke's Chemical Physics into the course of study. Such a change Prof. Cooke has been able to effect since his appointment at Cambridge, and now his chemical teachings fill a course of recitations and lectures commencing in the Sophomore year and covering two or three years. This is a great change in the policy of a college where this subject was formerly a by-word, and it offers every encouragement for efforts to secure a similar change in other leading colleges. For this reform, as for the high scientific character of his present work, Prof. Cooke will receive the hearty thanks and esteem of all teachers in this department of science.

8. Smithsonian Miscellaneous Collections.-Catalogue of the Publications of Societies and of the periodical works in the Library of the Smithsonian Institution, July 1, 1858. Foreign works. Washington, 1859. pp. 259, 8vo, with a Supplement.-The arrangement of this catalogue is geographical, commencing with Scandinavia and ending in Europe with Great Britain. It is followed by an alphabetical Index to Learned Societies, and another of miscellaneous publications, chiefly Journals. The Smithsonian Library possesses, as appears from this list, the Transactions in full or in part of 501 Institutions and Learned Societies, and series, more or less complete, of 254 Scientific Journals exclusively foreign. The domestic publications form the subject of another catalogue. It is a most valuable aid to the student in ferreting out the often enigmatical references constantly found in books of science, and for determining the probability of being able to verify such references by a visit to Washington, or by correspondence. Only those who have undertaken researches can appreciate the value of such an aid.