RIDAY morning, January 29th, the present Senior A's graduate from the school. The program for the day will be as follows: A few words to the class by our Principal, Mr. Childs; an address by Dr. Jordan, President of the Stanford University; and, as is customary, some choice music by the school.

Friday evening, in the Normal halls, the class holds its farewell reception meeting as a class for the last time, and parting from old associates and associations to "Find out their tasks," and then, "Stand to them."

Nor long ago Miss Washburn talked to us again about her Alaskan trip, dwelling particularly on glaciers. She told us, in her interesting way, much that was new about these "frozen rivers;" and she painted for us, with both language and crayon, a picture of the Alaskan glaciers that can not be obtained from books.

Our last lecture was given by Dr. Woods of Stanford University. The subject was Physical Culture, and was skillfully handled by the able speaker.

BEFORE many months have flown, the new Training School building will be completed. Work on the foundation is steadily progressing and the basement is already assuming definite proportions. The building is to be back of the Normal, with its front entrance on Seventh street, and it will be connected, in the near future, with the main floor of the Normal by an elevated corridor.

THE Senior classes met on the afternoon of Friday, January 15th, for the purpose of electing the new editoria! staff for the Normal Index Department of the PACIFIC COAST TEACHER. There was a full attendance of the classes, and, as is customary on these occasions, enthusiasm ran high.

The education which comes from an active connection with a journal or magazine is far from being inconsiderable. "Writing, Lord Bacon has said, “maketh an exact man," a truth which becomes more and more evident with practice in composition, and, may we not say, delightful, for there is a certain delight in the knowledge of a growing tendency to be exact, specific and discriminative.

In these qualities we believe the newly elected staff of this department already excels.

Mr. Sam H. Cohn was elected editorin-chief. The names of the editors will appear in the next number at the head of this department. Success to June '92.

SCIENTIFIC.

Designating the Relative Position of Objects in the Field of a Telescope.

By E. E. BARNARD.-Astronomer at Lick Observatory.

Regular astronomical observers, to avoid confusion, always refer to the west and east sides of the field of view of a

telescope as the preceding and following side, as indicated by the motion of an object moving across the field by the earth's rotation. Of two objects, that one which precedes, in their motion, is called the preceding object and the other the following. These for brevity, are indicated by the letters and f. As the astronomical telescope not only inverts but reverses the image and its motion, the substitution of these terms for west and east prevents many mistakes. From the inversion of the field the upper object is the southern and the lower the northern (as referred to a vertical to the equator). Between the zenith and the pole the reverse of this holds.

EXPERIMENT IN DIFRACTION.

A remarkably beautiful experiment with a telescope may be made by placing over the object glass-not necessarily in contact with it-a piece of fine wire gauze, and examining the planet Venus. or a bright star, such as Sirius. The difraction of the light in passing through the screen produces a series of gorgeously colored images or spectra of the planet, in the form of radiating tufts of colored light, with a pure white image of the planet in the center. The lowest magnifying power with a large field glass should be used. Perhaps a piece of coarse veil would serve nearly as well. OBLIQUE VISION IN OBSERVING FAINT OBJECTS.

Observers with a telescope take advantage of what is called oblique vision in observing very faint objects. From constant use the retina immediately back of the pupil becomes more or less dulled. If the eye is directed to one side of the field of view and an object in the center of the field is then examined by glancing obliquely at it, or "out of the corner of the eye," it will appear very much righter-especially if it is a faint ob

ject—nebula, comet or star. This is due to the fact that the light from the object then enters the eye obliquely and falls on an unused or more sensitive portion of the retina. By this means observers are often enabled to accurately measure some of the celestial bodies when they are wholly invisible by direct vision-a faint comet or star, for instance. This method is also of great value in observing the tail of a comet or the zodiacal light with the naked eye.

JUPITER'S SATELLITES.

The planet Jupiter is in a very unfavorable position for observing in February from its proximity to the sun. A few of the phenomena of the satellites may, however, be seen in the early evening.

In an astronomical telescope the satellites in the nearer parts of their orbits move from right to left, and in the distant portions, from left to right. A satelliti (or shadow) therefore in approaching transit will pass upon the disc of Jupiter at the right hand or following side. At occulation it will pass behind the planet. on the left hand or preceding side.

Following are a few of the phenomena. of the satellites that may be seen with a telescope during February.

These satellites are designated I, II, III, IV, according to their distances from Jupiter.

Tr.-Transit of a satellites across the disc of the planet.

Sh.-Transit of a satellites' shadow across the disc of the planet.

Oc.-Occultation of a satillite by the

21

55 25

22

5666

6

Eg Dis In

I Sh. In I Ec. Re Hence from this table, we find that on Feb. 4th at 15 minutes past 7 P. M. the shadow of the second satellite of Jupiter will begin to transit the disc of the planet.

For the month of February, satellite I will reappear from eclipse about 4 diameter of Jupiter on the following side.

It will be noticed on Feb. 14th, that the shadow of I is on the disc from 4 hrs. 59 min. to 7 hrs. 16 min. and will be about the middle of the planet at 5 hrs. 7 min. which will be a very favorable opportunity to see it.

When reappearing from eclipses, I will regain its full light in about one minute -the other satellites require a longer

time.

CONJUNCTION OF VENUS AND JUPITER.

A remarkably close conjunction of the planets Venus and Jupiter will occur on February 5th at 17 hrs. Washington mean time.

Unfortunately the nearest approach occurs after the planets have set to California. Australia and Japan, however,

will be more fortunate and will watch the gradual coalescence of the two bright planets into one bright star. At Sydney and Melbourne the opponent distance between the two will be less than a quarter of a minute of arc (about 14 seconds of arc.) It is not possible for the unaided eye to distinguish such a small quantity, the two planets will therefore appear as one. Such a close conjunction is exceedingly rare.

In California Jupiter and Venus will appear as two bright stars almost in contact. The distance between them, at the time of setting, being 16 minutes of archalf the opponent diameter of the moon. It will be a beautiful picture and one well worth seeing.

OBJECTS FOR OBSERVING WITH A SMALL TELESCOPE.

In noting the following objects for inspection with a small telescope, it will be presupposed that the observer has access to a star chart and is familiar with its use.

In estimating distances the following will be convenient references:

The distance between the two end stars in the belt of Orion is just three degrees, and the distance between either of these and the middle star is one and a half degrees. Between Castor and Pollox, in the Twins, is five and a half degrees. Between the "Pointers" in the Great Dipper five degrees. Between Aldebaran and the Pleiades, twelve and a half degrees. The apparent diameter of the moon is slightly over half a degree.

It is well to know the diameter of the field of the telescope so that estimates. may be made of the relative distances between objects under observation. Το determine this, take some star near the equator, one of the stars in the belt of Orion, preferably the upper one, and note the time it takes to centrally cross

Dividing this interval

the field of view. in seconds by 4 gives the diameter of the field in minutes of arc.

OBJECTS IN GOOD POSITION FOR OBSERV

ING IN FEBRUARY.

Great Nebula of Orion. Three or four degrees below (south of) the belt of Orion are three stars in a line pointing to the middle star of the belt. The lower star is the brightest-the upper one being quite faint. Between these two is a hazy star. This the great nebula, which is easily visible to the naked eye. The smallest telescope will

show it as an irregular mass of cloudy light, and with large instruments it is a marvelous object. A soft delicate filmy light, having the irregular form of a headless hat. According to Huggins this object is a mixture of several gases, notably hydrogen and nitrogen. The vastness of its real dimensions must be all but inconceivable. In the center of it a small telescope will show four little stars close together. They compose the multiple star Theta Orionis. Popularly called the "Trapezium of Orion."

Great Nebula of Andromeda. This fine object is easily found by first finding, with the aid of the map, the bright star Beta Andromeda, about twenty degrees south of Cassiopeia, and which is a few degrees west of the zenith at dark. Four and seven degrees north of Beta are two lesser stars. About two degrees west of the northern of these two stars, a glow of hazy light is easily visible to the naked eye. This is the great nebula. A small telescope readily shows it as an elongated or spindle shaped object. Only the photographic plate, however, shows its truly wonderful form. As revealed by photography, it consists of a condensed. mass of luminous matter surrounded by great rings of nebulosity-not unlike a

and his rings. In the brightest part of the nebula, a brilliant star suddenly appeared in the latter part of August 1885. After remaining visible for a few months this star totally faded from view. It had never been seen before, nor has it been seen since. From the record of the Spectroscope this great nebula seems to be a vast mass of gaseous matter under high pressure. As a naked eye object, the nebula has been known since the tenth century. From its great beauty it has been called the "Queen of the Nebulæ."

Cluster in Perseus. Fifteen degrees east of Cassiopeia the naked eye readily detects a rather large hazy spot of light. With a small telescope this is seen to consist of two beautiful clusters of stars. It is known as the cluster in Perseus and in a moderate telescope is one of the most beautiful objects in the sky.

The double star, Gamma Andromedae. Having found Beta Andromeda, in looking for the great nebula, it will be easy to find Gamma. It is similar in brightness to Beta and lies about twelve degrees north-east of that star. Very close to Gamma is a small star, of the seventh magnitude, which may be seen in a small but perfect telescope. The large star is orange, the smaller one greenish or blueish. Only a few years ago the small star was readily seen to be itself a close double, but for the past few years it has appeared single even in the great Lick telescope. One of the small stars has been passing between us and the other-the two being superposed. Burnham reports that with the great telescope the little star is now elongated, and in a few years the two will again be visible.

Mr.

Double star Castor. This, the western of the two bright stars in the head of the Twins, is a beautiful double star, the

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components of which are nearly equal. The two stars can be seen in quite a small telescope. These twin suns are revolving around each other in about one thousand years. Castor, and its neighbor Pollux, is easily found about forty degrees north and east of Orion.

The Pleiades. This beautiful cluster will repay examination with a small telescope. Indeed it is only with such an instrument that its beauty as a cluster is at all apparent. A good field glass gives perhaps the best view. The brightest star (Alcyone) near the middle of the group has three small companion stars close preceding it which are seen in a small telescope.

The principle stars of the Pleiades are drifting through space together and are really physically connected. They are at a vast distance from us, according to Dr. Elkin, and they are very many times larger than our sun. Photography has shown that these stars are connected with each other by a vast system of nebulosity which seems to cluster about the bright stars Alcyone, Merope, Maia and Electra.

we say there was in the air that every one of us has to have in order to live?" "Oxygen." The pupil decided that there must be oxygen in water. One in the class happened to know that there is also hydrogen. The new word is written on the board, and drilled on.

The class now carefully observed the following experiment: The test tubes were filled with water and inverted in a glass triangle also full of water. Two platinum points were next connected with

these tubes and also attached to a battery. The circuit was closed and the children immediately noticed the bubbles of gas rising in the tubes, and that it rises faster in one tube than in the other. As soon as the tube became full of gas, it was removed from the tumbler, (the finger being held over the opening,) inverted and the flame held at the mouth of the tube. "What has happened to the fire?" "The fire popped and went out." The flame was then held at the opening of the other tube and when questioned as to what they saw, such answers as, "The fire burns harder," "The fire burns better in the tube than out of it," were given. From previous study of the air the class knew that Master Oxygen is a jolly fellow who always burns. everything up, when left by himself, and the pupils, by a few questions from the teacher, soon decided that oxygen gas is in the second tube and that of course, hydrogen must be in the first.

Each step in the lesson was then carefully reviewed by the class. When lead to compare the amount of hydrogen that rose with the oxygen, they judged inaccurately, but upon being told, easily remembered having seen in the experiment. the hydrogen tube fill twice as fast as the oxygen tube.

When you go home to-night repeat to some one in your family, just what you