222 



SCIENCE. 



[N. S. Vol. XIV. No. 345. 



treated on October 8 remained alive over win- 

 ter. 



3. Peach foliage protected from rain and 

 dew, as in a greenhouse, sustains no ex- 

 ternally visible injury from spraying with either 

 Bordeaux mixture or copper hydroxide. Under 

 normal orchard conditions the leaves sprayed 

 with Bordeaux in a situation so as to be par- 

 tially protected from falling rain or dew are 

 the last to succumb to the injurious action of 

 the copper. 



4. The presence of deliquescent salts (as 

 Ca(N03)2 and CaClj) greatly accelerates the 

 iDJurious action of copper hydrate on the foliage 

 of the peach. 



5. Peach seedlings growing in a saturated 

 atmosphere are not injured by Bordeaux mix- 

 ture and but slightly by pure copper hydrate. 



6. Peach leaves growing in a saturated 

 atmosphere possess a thinner and much more 

 easily permeable cuticle than those growing in 

 a dry or less moist atmosphere. Following is 

 a summary of measurements of paraflBne sec- 

 tions stained with chloroiodide of zinc : 



Peach leaves. Thickness of cuticle 



of upper surface. 



Orchard Knoxville 1.17 micromillimeters 



Orchard California 1.21 " 



Seedling greenhouse 0.86 " 



Seedling in moist chamber 0.60 " 



7. The presence of a certain excess of lime 

 accompanying the copper hydrate on peach 

 foliage retards or possibly entirely prevents the 

 injurious action of the latter. This holds true 

 of lime applied either as the hydrate or at once 

 as the carbonate. The sulphate of lime does 

 not produce this eflfect. 



The writer believes that the above results go 

 far toward explaining the conflicting testimony 

 of different investigators along this line in this 

 country. So far as shown to date, no injury 

 will result to peach foliage sprayed with ordi- 

 nary Bordeaux mixture until a certain propor- 

 tion of the lime carbonate is washed out by 

 heavy dews or rain, when it at once begins to 

 manifest itself. One would thus expect but 

 little injury in an arid region like parts of Cali- 

 fornia. On the other hand, an atmosphere con- 

 taining abundant hygroscopic moisture, such as 

 is to be found in Georgia and Florida, would 

 supply conditions similar to those produced in 



the moist chamber as stated above, and thus 

 atone to a certain extent for the washing out 

 of calcium carbonate caused by precipitated 

 water. 



The practical application of this principle is 

 readily suggested. It may be possible to fol- 

 low up a spraying with Bordeaux mixture with 

 one or more of milk of lime and thus prevent the 

 injury which would otherwise occur. Experi- 

 ments carried out here this season thus far show 

 this method to be a success. Whether it will 

 remain so to the end of the season is yet to 

 be determined. There are, of course, other 

 questions to be taken into consideration, such 

 as the practical application of the method in 

 the commercial orchard, the effect of the lime 

 on the fungicidal action of the copper, etc. 



It is hoped in the forthcoming publication 

 above mentioned to describe in detail the ex- 

 periments above outlined, in addition to a 

 number of others finished and now nearing 

 completion, looking toward the physiological 

 explanation of the results obtained. 



Samuel M. Bain. 



University of Tennessee, Knoxville. 



CURRENT NOTES ON PHYSIOGRAPHY. 



THE NORTHERN ADIRONDACKS. 



A ' Preliminary Eeport on the Geology of 

 Franklin County,' KY., by H. P. Cushing(18th 

 Rep. State Geol., Albany, 1900, 73-128, 8 pi., 

 colored outline map) describes the northern side 

 of the Adirondack mountains and the drift- 

 covered paleozoic plain at their base. The 

 transition from one area to the other is rather 

 abrupt, but the height of the mountains de- 

 creases with some regularity towards the plain, 

 and branches of the plain enter valleys among 

 the hills. An old baselevel is inferred from 

 the systematic northward decrease of summit 

 heights, although its horizon is admittedly not 

 closely definable. The present valley system 

 is explained as of later origin, the result of 

 erosion following a slanting uplift. No dates 

 are given in this connection, although it is said 

 that ' the Adirondack region has been continu- 

 ously above sea level since Lower Silurian 

 times' (78), a statement that seems open to 

 doubt. The step-like descent of the mountains 

 toward Lake Champlain is explained ' by a 



