BOTANY. 785 



are reported: (Carefully waslied alfalfa roots, 0.127 to 0,5 per cent of 

 pure alumina; convolvulus roots, 0.059G to 0.4 per cent; Bermuda ^rass 

 roots, 0.011 to 0.12 per cent; lupine leaves, 0.013 to 0,037 per cent; linden 

 leaves, 0.0012 to 0.0025 per cent. 



These results indicate tliat alumina is present in considerable amounts 

 in plants with extensiveroot systems, but that it remains largely in the 

 roots and is found in only minute quantities in the leaves. 



Report of the botanist, B. D. Halsted {New Jersey Sias. Kpt. 1893, 

 pp. 2S'.)-436, Ji(/.s. 73). 



Si/nopsis. — The author gives a report on weeds, potatoes grown directly from the cut- 

 tings, the solaudi process of sun printing, and various fungus disenses (see j). 823). 



Report on weeds (pp. 200-312). — The author prepared as a part of the 

 Agricultural College and Experiment Station exhibitat the Columbian 

 Exposition a collection of the most common weeds of the country, which 

 were displayed in wing frames and as an herbarium. A case of 100 

 weed seeds was also shown. In collecting the material for this exhibit 

 an ojiportunity was offered for extending the check list of American 

 weeds, a revised list of which is given. Tliis list embraces 817 species, 

 representing 77 orders. An illustrated lecture upon weeds was pre- 

 pared, a synopsis of which is given. 



Potatoes by the direct method (pp. 312-318). — The author's attention 

 was called to siiecimens of seed potatoes that failed to produce plants, 

 in their stead snmll tubers were grown from the eyes, and all further 

 development stopped. In a few cases there was a feeble attempt to 

 send up shoots, but in all cases the yield was greatly reduced. Foreign 

 truckers are said to sometimes take advantage of this habit to produce 

 an early crop of potatoes. The reason for this unusual behavior seems 

 to be physiological, and whatever tends to weaken the seed may under 

 adverse atmosi)heric conditions j)roduce the result given above. 



The solan di process of sun printing (pp 318-323). — This process con 

 sists in exposing the subject, necessarily somewhat translucent, to the 

 sunlight in an ordinary printing frame with a sheet of sensitized i)ai)er 

 back of it, as in the ordinary way of printing from a negative. This 

 sun print when toned becomes the negative from which the pictures 

 may be printed, a piece of glass being interi)osed between negative and 

 print. The toning is done with kerosene for both negative and posi- 

 tive. As the object must be translucent, the nses to which this method 

 can be placed are limited, but any object that will allow any light to 

 penetrate may be so photographed if exposed long enough. Leaves, 

 thin sections of wood, rusts, leaf spots, blights, etc., are especially 

 adapted to this proeess. This method of printing is not new, but the 

 use of kerosene as a clarifying agent is the chief point of interest, as 

 it diminishes the time required for exposure and sharpens the details 

 of the positive picture. 



Shrinlca/fe of leaves in drying (pp. 32^326). — Numerous leaves were 

 printed by the solaudi process, after which they were prepared for the 

 16352— No. 9 3 



