4G8 



• KNOWLEDGE 



[Makch 31, 1882. 



and Cainlpri(lf;o crows as something Itetter than " inellicicnt 

 uiftlioi-ritics,'' Tlu'ii again, to hear these critics, one 

 might well believe tliat the ei;,'ht picked oarKiiicn of 

 uitlier l^niversity Imrdly ivuew how to get tlieir oars 

 out of tli<^ water w ithout crali-catehing. The way in whicli 

 they mistake cause and eflect is amusing. Tliey watch the 

 Camliridgi' or Oxford l>oat rowing with a strong wind on the 

 starlxianl l>eam, so that she is down on the stroke side for 

 awhiU- ; and wo hear tlie terrible news that, stroke and six, 

 or pcrliaps all the stroke side, " row too deep, tlx; conse- 

 quence being that they bring the boat down on th(,'ir side." 

 Tln! height of absurdity, however, was attained last week 

 in the Jt'/cree, which assuming the inferiority, or rather the 

 utter worthlessncss, of both the University crews (of " ineffi- 

 cient mediocrities ") this year, gravely hinted that it had 

 been attributed to favouritism in the selection of the 

 men to form the crews. This well informed sporting paper 

 Lopes the report may not lie true, but considers that if 

 it is untrue, it should be contradicted : so that Tom and 

 'Arry, after reading the paragraph, arc left under the 

 pleasing impression that " them nobs " can " nobble a 

 race " as thoroughly as the worst " dark rowers " on the 

 river. If Pendragon had ever attended Captains' meetings 

 at cithcB University, he would know liow pleasant would 

 be the fate in store for a " President " who should make up 

 a University crew of inefficient mediocrities, or from any 

 but the picked oarsmen of the best eights on the river. 

 That on some occasions there may have been one or 

 two men out of the "eight" who would have done a shade 

 better than one or two in the 'Varsity crew, may be 

 admitted : but readers of the R/'ferce may rest assured that 

 the President of either University Club selects ahcai/s, to 

 the best of his judgment, the eight men he believes to be 

 fittest. 



THE SUN IN APRIL. 



[Notice. — The foUowinff notes are prepared on the supposition 

 that those who will read them are provided with soaie almanac in 

 which the astronomical phenomena are announced. Tlie advanced 

 student of astronomy usually has the Nautictil Almanac, but for 

 the amateur, Whitaker's Almanac will be found amply sufficient. 

 Many other almanacs, though not so specially adapted to the re- 

 quirements of the amateur astronomer, contain much astronomical 

 information ; and scarcely any fail to indicate such matters as the 

 epochs of the lunar phases ; the hours of rising and setting of the 

 sun, moon, and planets ; the equation of time, and soon. It has 

 therefore not seemed desirable to cceupy space with such details, 

 but rather to provide matter which might prove of real assistance 

 to the student.] 



THE sun's path during the month of April, or rather 

 from March 20 to April 20, is shown in the accom- 

 panying map from "y to » ; that is, from the place where 

 the sun's centre crosses the equator ascendingly, or north- 

 wards, through the part of the ecliptic corresponding to 

 the sign Aries. On March 20, at 11 a.m., the sun passed 

 the point called the First Point of Aries, and spring com- 

 menced. His rate of motion at this time does not difler 

 much from his mean rate, and in the course of his passage 

 through the first sign, Ai-ies, he passes one of the points 

 of his annual course where he is at his mean dis- 

 tance and moves with his mean rate of motion. (This 

 occurs on April 1, and again after the autumnal etpiinox 

 on October 3.) But although during JIarch and April 

 the sun moves at nearly his mean rate along the 

 ecliptic, his path is at its greatest -inclination to the 

 equator. Thus, while he travels along 30 degrees of the 

 ecliptic, reaching the point 8, he has not advanced 

 30 degrees in right ascension, which is measured parallel 

 to the equator. We see that the point b instead of being 

 in 11. A. 21i., or 30°, he is only in R. A. Ih. oOm., or 57.V" 



(sec the illustrative map). The mean sun, therefore, 

 wliich is sujijiosed to travel at a uniform rate along the 

 equator, gains during March and April on the real 

 sun. liut we must not fall here into the mistake 

 made in some elementary tnsatises on astronomy (Mr. 

 Lockyer's, for instance), where it is said that there/ore 

 the clock gains on the sun. The sun's loss in right 

 ascension acts the other way. For as he moves annually 

 in a direction contrary to that of the diunial rotation of 

 the lieavens, the more slowly he moves in right ascension 

 the shorter distance has he to make u[> in coming to the 

 meridian. The eastwardly motion of the mean sun (from 

 right to left in our map) causes the difference of nearly 

 four minutes between a nif^n solar or civil day, and 

 the sidereal day. The smaller amount of the real sun's 

 eastwardly motion, measured parallel to the equator, causes 

 the real solar day in March and April to exceed the sidereal 

 day in less degree. Solar noon occurs sooner than it 

 would if the real sun moved like the mean sun. Accord- 

 ingly, whereas on March 20, at noon, the clock was nearly 

 71 min. faster than the sun, this araoimt has been 

 gradually diminishing day by day since then ; it will be 

 less than t min. on the day when this number of Know- 

 ledge is published, little more than 2 min. on Thursday, 

 April 7, 1 1 ••")I sec. on April 14 ; while at noon on April 15 

 the sun will be 347 sec. before the clock, and about 1 min. 

 before the clock when the sun completes his passage 

 through the sign Aries. 



It is to these changes that the seeming irregularity of 

 the day, as measured from sunrise to sunset, by the clock, 

 is due. If the time of solar noon corresponded to noon by 

 the clock, the hour of smirisc would be almost exactly as 

 many hours and minutes before as the hour of sunset would 

 be after the time of noon. But when the hour of solar 

 noon follows the hour of clock noon, the time of sunrise 

 comes so manj- minutes nearer to clock noon, while the 

 time of sunset is as many minutes farther from clock 

 noon ; in other words, the sun seems both to rise later and 

 to set later than it does by solar or natural time. Thus^ 

 on March 20 the sun rises at 6h. 5 m., only 5 h. 55 m. 

 before noon, and sets at 6 h. 10 m., or by so long (15 m. 

 longer) after noon.* Wliereas, on AprU Itfth, when the 

 equation of time vanishes, or the real sun and the mean 

 sun are together (in right ascension), the sun rises at 

 5 h. 6 m., and sets at 6 h. 54 m., in each case G h. 54 m. from 

 noon. 



Asthma and Tobacco. — In reply to J. W. Brookes, I beg to state 

 that tobacco is sometimes recommended to persons suffering from 

 asthma, on account of its influence in deadening temporarily those 

 nerves upon whose irritation the asthmatic spasm depends. Troua- 

 seau, an eminent French physician, who suffered from this com- 

 plaint, mentions that " it often sufficed for him to take a few whiSs 

 from a cigar to free himself from his asthmatic trouble." And, on 

 the other hand, he says that he got an attack of asthma whenever 

 ho remained in a room in which there was a bouquet of violets. The 

 aroma from the violets acted as a stimulus to the na£al nerve- 

 twigs, which stimulus was communicated to the ner^■e3 governing 

 the bronchial tubes, and thus contraction of those tubes, and conse- 

 quent difficulty of breathing, were produced. Tobacco, on the other 

 hand, causes temporarj* paralysis of the same ner\-es, and rendew 

 them incapable of producing contraction of the air-tubes. But its 

 effects are merely palliative, not curative. — J. SIi IK Howie. 



* Xote that on this day, the sun, being on the equator, would rise 

 at six and set at six were it not for refraction (almost exactly, but 

 tlie progression of the sun across the equator causes a slight dif- 

 ference, the sun being south of the equator when rising, and norA 

 of the equator when setting). But refraction, by raising him into 

 view before he has really crossed the plane of the horizon, and 

 keeping him still in view after he has really passed over it, makes 

 the day last rather longer than twelve hours on the day of the 

 equinox. 



