48 



NATURE 



[April 24, 19 19 



carriage of the Sopwith machine soon after start- 

 ing, a gain of several miles per hour being thus 

 rendered possible owing to the decreased head- 

 resistance of the machine. A daylight landing is 

 a necessity under these conditions, and a slight 

 crash is inevitable. 



The time of crossing is estimated at approxi- 

 mately twenty hours, and some interesting figures 

 relating to this point given in a report of the 

 Meteorological Section of the Air Ministry were 

 referred to in last week's Nature. These figures 

 are based on the average of the weather rep>orts 

 available, and show that under the best conditions 

 the time of crossing for a machine with a speed 

 of 100 miles per hour, flying from west to east, is 

 only 14^ hours in the month of April, and under 

 the worst conditions 23 hours. The correspond- 

 ing times for an east-to-west crossing are 21 and 

 36 hours. The advisability of a start from the 

 American side is thus plainly demonstrated. 



Although Mr. Hawker, with his Sopwith 

 machine, was the first to be prepared for the 

 start, it seems likely that prevailing bad weather 

 will give other competitors time to get ready, and 

 that the Atlantic attempt will be of the nature of 

 a race. It is to be hoped that the desire to be 

 first across will not lead any competitor to start 

 before the weather conditions are reasonably 

 favourable, as the risks are sufficiently great 

 under the best conditions, and the loss of such 

 experienced pilots as those engaged in the present 

 attempt would be most regrettable. Meanwhile, 

 every endeavour will doubtless be made to choose 

 the best moment for the start, and we will hope 

 that before many days are past a new and great 

 triumph will be added to the annals of aero- 

 nautical science. 



THE FOOD REQUIREMENTS OF MAN. 

 n^HE Food (War) Committee of the Royal 

 J- Society has recently issued a report^ on the 

 food requirements of man and their variations 

 according to age, sex, size, and occupation, which 

 summarises existing knowledge in a manner intel- 

 ligible to the ordinary citizen. The customary 

 units of measurement are carefully defined, and it 

 is suggested that the energy requirements of those 

 engaged in various occupations should be esti- 

 mated in terms of the amount of energy necessarily 

 set free in the body to ensure equilibrium under the 

 given conditions. 



A provisional classification is into sedentary 

 work, where the excess expended during eight 

 hours' work over that transformed during eight 

 hours' sleep is not more than 400 Calories; light 

 work, the excess being 400-700 Calories; moderate 

 work, 700-1100 Calories; heavy work, 1 100-2000 

 Calories. The method is illustrated upon the data 

 of Becker and Hamalainen, the food requirements 

 of males being found to vary from 2750 Calories 



1 Report on the Food Requirements of Man and their Variations according 

 to Age, Sex, Size, and Occupation. Pp. 19. (London : Harrison and Sons, 

 1919.) Price IS. M. 



NO. 2582, VOL. 103] 



for a tailor to 5500 for a woodcutter. In the fol- 

 lowing section the influence of external tempera- 

 ture is discussed, regret being expressed that the 

 statistics of consumption during different months 

 of the year are so inadequate that valid inferences, 

 cannot be drawn from them. 



The energy requirements of women are dealt 

 with on the same lines as those of men, the provi- 

 sional figures ranging from 1783 Calories for a 

 seamstress to 3281 for a laundress (net energy 

 values), the food requirements of the average i 

 working woman being placed at 2650 Calories per 

 diem. ' 



In the following section the scanty data concern- j 

 ing the needs of children and adolescents are epito- \ 

 mised, and the report ends with a cautious descrip- 

 tion of the qualities of the proximate principles 

 and their respective rdles in a dietary. The final 

 sentence runs as follows : ' ' The above report 

 shows how very inadequate is our present know- 

 ledge of the science of nutrition, and demonstrates 

 the necessity of renewed investigations of almost 

 every point discussed in it." 



We do not know whether this sentence, express- 

 ing the considered opinion of a committee fully . 

 representative of all departments of science con- I 

 cerned with the subject of animal nutrition, will | 

 be taken to heart by the Government and people of 

 this country, but the measure of attention it 

 receives will be a measure of the real acceptance 

 by the nation of the gospel of science. Further 

 progress in the science of nutrition chiefly depends 

 upon the accumulation of accurate details. We 

 already know, for instance, that the food require- 

 ments of a labouring man vary enormously with 

 the nature of his avocation, and we also know how 

 these requirements can be experimentally deter- 

 mined ; we know that in the hani-working classes 

 the proportion of the total income expended up>on 

 food often approximates to 50 per cent. This is 

 the extent of our knowledge. Excepting the 

 armed forces, there is not a single class of the 

 community, not one occupational group, the 

 average energetic needs of which have been mea- 

 sured -upon a scale which entitles the measure- 

 ments to be taken into serious consideration as 

 data for estimating the income necessary to ensure 

 the preservation of a fit standard of life or the 

 general food requirements of the nation. To 

 secure this knowledge^ — -but one item in the long 

 catalogue of defects — organised research extend- 

 ing over years is necessary, research neither par- 

 ticularly attractive in itself, nor calculated to yield 

 spectacular results which can be made interesting 

 to the readers of the daily Press. The contribu- 

 tion of each individual worker must be small ; the 

 ultimate value of the sum of results would be 

 immense. 



It remains to be seen whether we have the 

 faith in science and the patience which will be 

 necessary to replace the scattered fragments, 

 which are all we now have, by a well-compacted 

 body of exact information. 



