January 4, 1894] 



NA TURE 



225 



what will be its effect upon the typical examples in the 

 text, worked first by the new process, and secondly by 

 the old method of double altitude. 



On page 30 an example (§ 32) is taken from Lecky, 

 which will answer the purpose. 



The data are as follows. Lat DR 32 15' N. 



Bearing. 



March 7, 1880. 



Altitude. 



S. 25 E. 

 S. 57 W. 



Times by chron. 



h. m. s. o ' " 



ilh. a.m. ... I II 3'S ••• 5° o o 



3h. p.m. ... 5 II 1-2 ... 33 17 45 



Sun's declination, 4' 59 15' S. for first observation; 

 4- 55' 30" S. for second observation. 



Let us suppose that an error of 2' occurs in the second 

 altitude, the one treated for reduction to the meridian. 



The error in latitude {dl) produced by an error in alti- 

 tude {(iz) is given approximately by the formula 



dl — sec A^ . ci'z, 

 where Aj is the azimuth of the body. 



Thus (// = sec 57° X 2', or 3' 40" nearly. 



But if treated, so as to take in both observations, by the 

 double altitude process, 



sin A. 



di = 



dz, 



sin (Ai + Aj) 



where A^ = 57", A2 = 25"", the azimuths being reckoned 

 from south in each case. Thus 



sin 82° ^ 



So that in one case a reasonable error in altitude gives 

 an error in latitude of nearly 4', in the other of less 

 than i'. 



One other instance will perhaps suffice. On page 36 

 an example from Riddle is worked out, wherein an error 

 of 2' in altitude would produce an error of 18' upwards in 

 latitude. 



Such a result at once condemns the observation. Indeed, 

 for the purpose of accurate determination of latitude, 

 the double altitude stands out among the various methods 

 a very king. In other cases, as in the meridian altitude, 

 we are satisfied if the latitude is no more in error than 

 the original observation. In a double altitude, taken 

 under advantageous conditions, only a fraction of the 

 error in altitude appears in the final result. 



It is somewhat remarkable that Mr. BuUer's evident 

 appreciation of Sumner methods has not made him more 

 familiar with the main principles which apply equally to 

 all classes of observations. 



Every observation furnishes the observer with a circle 

 upon the globe, a straight line upon the Mercator's chart, 

 on which to place his position. The circle has the sun's 

 projection on the earth for its centre. The line has the 

 sun's line of bearing perpendicular to it. 



If this line of position is inclined at a very acute angle 

 to the meridian, that is, if the body observed is near the 

 prime vertical, it is evident that a very small increase in 

 the perpendicular drawn from the sun to the line of 

 position, that is, a very small increase of zenith distance, 

 will produce relatively a very large difference of latitude. 

 And thiscondition,coupled with the impossibility of obtain- 

 ing accurate altitudes at sea, is sufficient to account for 

 the restriction of ex-meridian observations to a point or 

 two in azimuth from the meridian. 



The British seaman, therefore, had better pause before 

 he throws overboard his Norie or his Raper, and takes to 

 his heart the new Buller methods. 



The greatest self-confidence, the most implicit 

 belief in the reality of the mission to which he has 

 been called, will not enable Mr. Buller to find the 

 latitude accurately by a single altitude near the 

 prime vertical, for the very simple reason that the 

 error (even when supposed small) which must be expected 



NO. 1262, VOL. 49] 



in the altitude produces a large error in the latitude, and 

 thus vitiates the result. 



If he would make the ex-meridian method available 

 as he proposes to do, at almost any time of day, the 

 author must supplement his treatise by the invention of 

 some appliance for measuring altitudes very much 

 superior to any now in use. 



Pending its production the very pertinent question 

 asked in page 36, "We have known long enough how 

 to get a fairly correct A. T. S. from an observation near 

 the Prime \'ertical and the latitude D. R., but who has 

 yet shown how to obtain the True Latitude" t must re- 

 main unanswered. 



There is indeed freshness in the " New Method of 

 Navigation," Part I., but no light. That perhaps will be 

 supplied by Part II. G. 



VOICES FROM ABROAD. 



THE following literal translation of parts of an article 

 recently published in the Chemiker Zeitung (Nos. 

 85 and 86, 1893) is an appropriate addendum to a recent 

 article of mine in this j ournal. It must be sorrowfully 

 admitted that in essential particulars the picture is a true 

 one. Henry E. Armstrong. 



" Notwithstanding the enormous industrial develop- 

 ment of England, the appreciation of science by technical 

 v.'orkers is inconceivably slight, the main cause being 

 deficient comprehension. The Englishman is conser- 

 vative in all his customs, in his way of living, and not 

 less in his methods of manufacturing, so that there are still 

 very many manufacturers who would be as little prepared 

 to place the control of their works in the hands of a 

 scientific chemist as to convert them into philanthropic 

 institutions. At present great efforts are certainly being 

 made to alter this condition of affairs by the aid of 

 technical schools modelled on German lines, but 

 opinions as to the value of these schools are as 

 yet much divided ; and, indeed, for various reasons 

 their ultimate success is doubted. In the first place, 

 it is to be borne in mind that these institutions 

 are not under State control, but are governed and con- 

 trolled by local boards. Moreover, the preliminary 

 training which their students have received is not to be 

 compared with that of students in the German institu- 

 tions, as an education such as is given in the German 

 Realschulen and Gymnasiums— of the character given in 

 England at most by the grammar schools— is only pro- 

 curable by those who are well off, owing to the enor- 

 mously high school fees (about ^20 or 400 marks a year). 

 The possibility of consolidating and widening the tech- 

 nical training by a short subsequent course of scientific 

 study at the University is absolutely out of the question 

 in most cases, owing to its extreme costliness. It is 

 therefore probable that these schools will but produce a 

 number of half-educated persons who will take up posi- 

 tions as chemists and will thereby but bring the chemist 

 proper into discredit. 



" It is clear that under these circumstances there is but 

 very little prospect that a chemist coming to England 

 will find a suitable position. I cannot sufficiently strongly 

 caution ' young chemists ' against coming to England on 

 the chance of picking up something good, even when 

 provided with good introductions. So few analysts are 

 in demand here that the chance of securing such a post 

 is most uncertain. Works and laboratories in which 

 scientific work is systematically carried on scarcely exist, 

 not one even of the English aniline colour works having 

 a scientific laboratory worthy of the name. The ' young 

 chemist' has therefore very little chance of securing an 

 appointment, as he does not possess the necessary 

 qualification for a works post, that is to say experience, 



