340 



NA TURE 



[September i6, 19c 9 



high latitudes have great disadvantages so far as 

 observations are concerned. The stars have disap- 

 peared, to be seen no more for five or six months, and 

 the sun is so near the liorizon, owing to its low 

 declination, that the meridian altitude, upon the 

 measurement of which the latitude usually depends, is 

 not high enough to give a satisfactory result, owing 

 to the uncertainties of the refraction correction, and, if 

 a sextant and artificial horizon are used, to the great 

 difficulty in making the observation at such a low 

 altitude, and unavoidable distortion of the sun's 

 image. For good results it is a maxim with geo- 

 graphical surveyors that no altitude should be taken 

 that is less than 25° or 30°. 



A meridian altitude of the sun only a little above 6°, 

 which is what would be observed at the poles on .\pril 6, 

 or between 11° and 12°, which would be the amount 

 for April 21, would not be likely to furnish a very 

 exact latitude, even if taken with a first-rate instru- 

 ment under favourable climatic conditions, much less 

 so when these are not favourable and when the ob- 

 servations are made wMth the small portable instru- 

 ments which alone can be carried by the explorer on 

 a rapid dash to the pole, when every ounce of weight 

 is a serious consideration. 



Dr. Nansen, after leaving the From, took with him 

 on his famous sledge journey a small altazimuth, 

 with 4-inch circles, and a pocket sextant with an 

 arc of if inches radius, both of which, by means of 

 verniers, read to single minutes. It was with the 

 pocket sextant, however, that his farthest north lati- 

 tude observation was made, using the natural horizon, 

 and he admits that the result cannot be depended upon 

 to a minute or two 



Captain Cagni observed with a sextant, and in re- 

 ferring to his farthest north latitude, which depended 

 upon an altitude of about 12°, states that he used 

 both the artificial horizon and the natural horizon, 

 which latter was very distinct. 



Coming now to the .Antarctic regions. Captain Scott's 

 expedition was well provided with instruments, but 

 his highest latitudes on the southern journey were 

 taken with a small theodolite. In the case of this 

 expedition, the dates when the high latitudes were 

 reached were later on in the summer, so that the sun's 

 southern declination, and consequently its meridian 

 altitude, was higher. 



This same remark also applies to Mr. Shackleton's 

 recent expedition, for on January 3, when the last 

 observation on his long journey to the south was 

 made, the sun's meridian altitude was about 25° 33', 

 which resulted in a latitude of 87° 22', the further 

 distance travelled south of this depending for its 

 measurement chiefly on the sledgeometer, which 

 throughout the journey had been found to agree 

 well with the latitudes observed. On his journey 

 Mr. Shackleton used a 3-inch transit theodolite, 

 reading to single minutes, and the adjustment 

 of which had been thoroughly tested. He also had 

 the advantage of observing on ti'rni firina instead of 

 moving ice, so altogether his resulting latitudes doubt- 

 less compare very favourably, as regards accuracy, 

 with those of other polar e.xplorers. 



As regards the effect of extreme cold on the refrac- 

 tion correction of the altitude, it may be interesting to 

 note that, for an altitude of 11°, there is a difference 

 of just above i' for a change of temperature from +50° 

 to -60° F. 



Sextant observations taken with a glass plate arti- 

 ficial on moving ice would be most untrustworthy, for, 

 in addition to the probable sources of error already 

 referred to, there may be slow oscillations of the 

 water, tidal or other, that may affect the level of the 

 reflecting surface considerably. 



NO. 2081, VOL. 81] 



CHEMISTRY IN THE SERVICE OF THE 

 STATE. 



IT is generally known in chemical circles that Sir 

 Edward Thorpe is relinquishing the post of prin- 

 cipal chemist at the Government laboratory, which 

 he has so ably held for the last fifteen years. In the 

 closing paragraphs of the present report ' he notes 

 that it is the last document of the kind he will 

 have the honour of submitting to the Treasury, and 

 takes the opportunity of directing attention to the 

 great increase which has occurred in the work of 

 the laboratory during the period in question. It 

 appears that the number of samples examined yearly 

 is now more than double what it was fifteen years 

 ago, the actual figures being 76,513 in the year 1894, 

 and 176,935 in 1908-9. 



Naturally there is not much of strictly scientific 

 importance to be found in the record of an establish- 

 ment devoted to " the daily round, the common task " 

 of acting as chemical .Abigail to all and sundry 

 Government offices. Yet in its applications of 

 chemical science to civic requirements Sir Edward's 

 department touches the public welfare at many points; 

 and in illustration of this some gleanings from the 

 pages before us are not without interest. For 

 statistics, in which the report abounds, the reader 

 may be referred to the publication itself. 



The business of the laboratory is subdivided into 

 three main classes. Articles examined for the two 

 great revenue departments. Customs and Excise^ 

 form by far the largest number of samples. .\ con- 

 siderable amount of work, however, is submitted by 

 other branches of the executive, especially the Board 

 of -Agriculture, the India Office, the .Admiraltv, the 

 Board of Trade, and the Office of Works. Finally, 

 samples, relatively few in number, but important as 

 being objects of dispute in legal proceedings, are re- 

 ferred to the laboiatory for examination under the 

 provisions of the Sale of Food and Drugs -Act and 

 the Fertilisers and Feeding Stuffs Act. 



In its role of revenue chemist, the laboratory Is 

 required to hold the balance fairly between the Ex- 

 chequer on the one liand and the maker or importer 

 of taxable commodities on the other. Alcoholic 

 liquors, sugar, tobacco, tea, coffee, and chicory 

 naturally furnish the greater number of samples for 

 analysis, since they are the chief dutiable articles 

 in this country. But in safeguarding the revenue de- 

 rived from these products it is also necessary to 

 analyse numerous other articles ; thus the principal 

 chemist remarks that " the duty on chicory involves 

 the examination of many substances botanicallv allied 

 to it, such as dandelion and burdock roots." Genuine 

 cider, again, is not liable to import duty, but samples 

 are analysed nevertheless; for "if evidence is found 

 that spirit has been added," the cider comes under 

 the tariff as a preparation containing spirit, and is 

 taxed accordingly. It is noted that a large proportion 

 — more than 13 per cent. — of certain beverages sold as 

 temperance drinks contained an excess of alcohol, the 

 quantity ranging from 3 to 11 per cent, of proof 

 spirit. 



.Among other miscellaneous matters, an investiga- 

 tion into the character of the spirits usually sold to 

 the labouring populace was undertaken. Such 

 phrases as " adulterated, maddening liquor " are 

 common in the mouth of the well-meaning but unin- 

 formed temperance enthusiast. The results of an 

 impartial inquiry, however, lend no support to the 

 charge of adulteration. Samples of whiskey, gin, 

 rum, and brandy were purchased in the ordinary way 



1 Report of the Principal Chem'st upon the work of the Government 

 Laboratory for the Year ended March 31, 1909. Cd. 4771. Price 3</. 



