634 EXPEBIMENT STATION EECORD. [Vol. 87 



tinued cold completely arrested growth for the time being, and resulted in a 

 very great reduction of the fruit crop. 



Fruit injury during the fumigation of citrus trees, R, S. Woglum (Fruit 

 World Austral., 17 {1916), A'o. 5, pp. 70-72). — Giving the results of observations 

 on the degrees and phases of fruit pitting after the use of cj'anld gas to kill 

 insects on citrus trees, the author holds that the cyanid gas itself is the basic 

 cause of general fruit pitting, other factors being the strength of the gas used, 

 length of exposure, condition of plants treated, and moisture, along with minor 

 or contributing factors. 



Mechanical injury, favoring the gas injury, is caused by drawing the tents 

 over the trees, especially when they are wet or when the tent poles are low. 

 Pressures on the growing fruit appear to weaken resistance near such points, 

 as in cases where fruits are pressed together. Trees which have been sprayed 

 with Bordeaux mixture should not be fumigated for about a year after spraying, 

 as leaves and fruit may be dropped as a re.sult of such treatment. 



The history and legal phases of the smoke problem, L. Johnson (iletallurg. 

 and Chem. Engin., 16 (1917), No. 4, pp. 199-204)- — Dealing very briefly with the 

 history and bearings of smoke-injury problems, the author reviews some phases 

 of the investigation carried out by, or in connection with, the Selby Smelter 

 Commission selected to investigate the questions arising in the Selby smelter 

 smoke zone (E. S. R., 34, p. 716 ; 35, pp. 133. 243, 244). 



It is sjiid to have been found that dust and acid vapors were practically negli- 

 gible factors In the fume problem so far as vegetation Is concerned, any damage 

 actually done being traceable almost wholly to sulphur dloxid. Vegetation can 

 stand on the average, it Is said, 50 times the strength of sulphuric acid that 

 it can bear of sulphur In the form of sulphur dloxid, the latter, however, pro- 

 ducing little or no injury when the plants are not In leaf. Both crude sulphur 

 and sulphuric acid increased crop yields in most Instances, and practically 

 without exception In alkaline soils. When leaf stomata were clo.sed, as in dark- 

 ness, the plants were very resistant to .sulphur dloxid. 



Four prominent factors In this connection were light, humidity, temperature, 

 and direction of the wind (where the latter Is constant, pufTs of wind having 

 but little Influence In this connection). Much of the injury previously ascribed 

 to smoke Is said to have been due to such factors as fungus diseases. 



FIELD CROPS. 



The experimental error in field trials and the effect on this error of various 

 methods of sampling, C. Miyake (Ber. Ohara Inst. Landw. Forsch.. 1 (1916), 

 No. 1, pp. 111-121, flgs. 2). — The experimental error of field tests with barley 

 and rice on single unit plats, successive unit plats, and scattered unit plats is 

 discussed, and data giving the standard deviation on the plats and the estimated 

 standard deviation are pre.sented In tabular form. The conclusions reached 

 from those data are that the standard deviation decreases with the size of the 

 plat, that it Is smaller with the scattered unit plats than with the successive 

 unit plats, and that the scattered unit plat method Is superior to the successive 

 unit plat method In point of sampling. 



The author found the probable error on a ■^■ncre plat of barley to be about 

 ±3.3 per cent, and of rice about ±1.8 per cent. He concludes that the probable 

 error In plats of this size is about ±2 per cent as contrasted with the results 

 obtained by Hall and Wood (B. S. R., 26. p. 732), from which they calculated 

 the probable error In field experiments to be approximately ±5 per cent. He 

 attributes this difference to the more Intensive cultural methods employed in 

 Japan. 



