252 



SCIENCE. 



[Vol. L, No. 9. 



The account of the Rothamsted experiments 

 on wheat, from the pen of Mr. Lawes, which 

 is appended to the report, will be read with 

 special interest, as showing what important 

 gains to our knowledge may result from such 

 experiments as those initiated at Houghton 

 Farm. 



The papers on agricultural physics contained 

 in the second report relate to local meteor- 

 ology and soil-temperatures. Under the first 

 of these subdivisions the most interesting state- 

 ment is, that local predictions, based on the 

 signal-service and on local observations, were 

 made at noon for the succeeding twenty-four 

 hours, with only two per cent of error. Con- 

 fidence in them was established, and they 

 served an important purpose for the time 

 during which they were issued. The obsei'- 

 vations on soil-temperatures will, of course, 

 j'ield more trustworthy averages when based 

 on more than a single season's work ; but 

 results of value are already obtained. Eight 

 thermometers with the bulbs immersed in oil 

 within wooden cases, to prevent change of 

 record during their observation, were placed 

 at the surface, and at depths of three, six, and 

 nine inches, and one, three, five, and eight feet, 

 and were obsei'ved hourlj^ between seven a.m. 

 and nine p.m., from May to October, 1882, and 

 sometimes throughout the twenty-four hours. 

 The soil was gravel upon hardpan and claj'. 

 The observations are elaborately discussed by 

 Mr. Penhallow, who obtains the following 

 results. The penetration of the surface-heat 

 to a depth of three inches requires one and a 

 half to two hours; to one foot, eight to ten 

 hours : hence, at a little greater depth than the 

 latter, the diurnal waves of temperature would 

 be reversed. Hourly change of temperature 

 ceases at about eighteen inches, and daily, near 

 eight feet ; but these, as well as the average 

 daily variations, being only for the hours from 

 seven a.m. to seven p.m., need supplementary 

 observations to show their full measure. The 

 use of minimum thermometers would greatly 

 increase the value of the results. Irregulari- 

 ties in the dailj* temperature-curve are con- 

 sidered first as shown in a diminished total 

 variation (' mean depression of hourly varia- 

 tions '), and, second, as seen in marked irregu- 

 larities in the curve ('sudden depressions'). 

 The first of these is found to be always con- 

 nected with rainfall and consequent excess of 

 moisture in the soil, probablj' aided b}' absence 

 of dii'ect sunshine ; the second generally comes 

 either from a temporary obscuration of the 

 sun, as \)y a passing cloud, or about as fre- 

 quently from the reaction after a sudden rise 



of surface-temperature much above that of the 

 soil below. 



Of more interest are the comparative results 

 of observations made in June, three inches be- 

 low the surface, in one uncultivated, and two 

 plots of cultivated ground, referred to in the 

 report as a and b. One of the cultivated 

 plots, a, had been treated with composted 

 stable-manure ; the other, &, with an equiva- 

 lent mixture of commercial fertilizer ; and both 

 were planted with corn. The uncultivated 

 ground had the greatest daily range, chiefly 

 from its higher maximum temperature ; plot a 

 had the least range, as its minimum was ^° 

 to 1° C. higher than in plot 6. This dimin- 

 ished variation would seem to result from heat 

 evolved by the decomposing manure. 



All the observations are neatlj^ recorded in 

 tables and diagrams. Their onlj' inconvenience 

 arises from the use of even numbers of feet or 

 inches in determining the depths for observa- 

 tion, while the records are kept in fractional 

 centimetres; so that 3, 6, and 9 inches are 

 always rendered 7.6, 15.2 and 22.8 cm. One 

 system or the other should be fully adopted. 

 As the first season of observation includes only 

 the warmer months, studies of frost are not yet 

 published. 



FOSSIL ALGAE. 



Apropos des algues fossiles. Par le marquis de Sa- 

 PORTA. Paris, Masson, 1882. 76 p., 10 pi. 1.4° . 



Ik a fine imperial quarto, the author criti- 

 cally examines the nature of some impressions 

 described by phj'topaleontologists as remains 

 of fossil Algae, but which a Swedish naturalist, 

 Nathorst, in a considerable work published at 

 Stockholm (1881), has considered as repre- 

 senting tracks of invertebrate animals. In his 

 memoir, Nathorst illustrates b}' a large number 

 of figures the tracks and impressions which 

 the author himself and others have observed, 

 as produced by the movements of small crabs, 

 insects, worms, even of water-currents and 

 waves, upon sand, or soft, muddy surfaces. 

 As points of comparison, the Swedish author 

 gives a list of the works where, to his belief, 

 are represented so-called Algae corresponding 

 to his figures. Among the memoirs quoted 

 in the list are Saporta's Faleontologie frangaise 

 (vol. i.) — where, among the Jurassic plants, 

 all the Algae, excepting Itieria and perhaps 

 one or two others, are considered as true 

 tracks — and the Evolution du r^gne v&gMal, 

 by Saporta and Marion, where most of the 

 impressions described as Algae are regarded 

 as tracks of divers kinds. It is to defend his 



