364 



SCIENCE. 



composition of these substances may be compared by ar- 

 ranging their formula; in the following manner : 



C12 H 20 O10, or C, 2 H10 O10 = Starch. 



C. 2 H 22 O n , or C J2 H u On = Cane Sugar. 



Cu H 2 4 O12, or C12 H12 O12 = Grape Sugar. 

 Grape-sugar is largely diffused throughout the animal 

 kingdom, and is found in most of the sweet tasting fruits. 

 It is contained in the honey of the bee, and is separated 

 in large quantities in the urine of those unfortunates who 

 suffer from that disease of the kidneys called diabetes 

 mellitus. Grape-sugar is not only found in nature but 

 can be produced chemically. Thus it is formed as a re- 

 sult of the action of diluted acids, diastaste, gluten, sal- 

 iva, etc. on starch, and for this reason starch is used for 

 its production on a large scale. 



The fullest directions are given in this work for the 

 manufacture of glucose from starch, and we congratulate 

 the publishers on producing a book at a moment so 

 apropos, and we regret we cannot devote more space to 

 the subject; we advise, however, all interested in this new 

 and rising industry to obtain a copy of the work, for it 

 apparently presents all the tacts bearing on the manu- 

 facture of glucose, in a very convenient form. 



REPRODUCING DRAWINGS, DESIGNS, &c. 



The following method of reproducing drawings, &c, in 

 any desired color, has been patented by M. M. Tilhet, of 

 18 Rue de la Paix, Paris. The paper upon which the design 

 is to be reproduced in order to'prepare a negative copy is 

 first passed through a bath composed of the following ma- 

 terials in about the proportions given : White soap, 30 parts 

 by weight ; alum, 30 parts ; Flanders glue, 40 parts ; the 



white of eggs or albumen beaten up, 10 parts ; glacial acetic 

 acid, 2 parts ; alcohol at 60 degrees, 10 parts ; water, 500 

 parts. The paper, after having been removed from this 

 bath, is passed through a second bath composed as follows: 

 Burnt umber, ground in alcohol, 50 parts by weight; black 

 pigment, 20 parts ; Flanders glue, 10 parts ; water, 500 

 parts ; bichromate of potash, 10 parts. The paper having 

 been thus treated must be kept when dry in a dark place. 

 In order to prepare positive paper for the prints, a bath is 

 used similar to the last, but without the umber, for which 

 black pigment is substituted. Or, if it is desired to obtain 

 colored proofs instead of black ones, the black pigment is 

 replaced by a pigment of red, blue, or any other desired 

 color. To prepare the copies, the design or drawing is 

 placed in an ordinary photographic printing frame, the back 

 of the design being next to the glass, and a sheet of nega- 

 tive paper prepared in the way first described is placed in 

 contact with it. The frame ia then exposed to light, two min- 

 utes exposure being sufficient in good weather. The sensitive 

 paper is then removed from the frame in a dark place and 

 is placed in water, when the design becomes visible in 

 white, and the paper is then allowed to dry. In order to obtain 

 positive pictures from the negative thus prepared, the latter 

 is placed in the printing-frame with a sheet of the positive 

 paper prepared in the manner above described in contact 

 with it, and after exposure to light for a sufficient time, that 

 is to say, about two minutes, the positive paper is removed 

 in a dark place, and is plunged into water, which removes 

 the part of the pigment which has not been affected by the 

 light, without its being necessary to touch it. Any number 

 of copies of the design or drawing may be produced by the 

 novel method described upon any kind of paper, and in any 

 color or colors. The proportions of the different mateiials 

 used to prepare the baths as above described may be varied 

 to suit varying circumstances, such as the weather and the 

 character of the design or of the paper. 



METEOROLOGICAL REPORT FOR NEW YORK CITY FOR THE WEEK ENDING JULY 23, 1881. 

 Latitude 40 45' 58" N.; Longitude 73 57' 58" W.; height of instruments above the ground, 53 feet ; above the sea, 97 



feet ; by self-recording instruments. 



BAROMETER. 



THERMOMETERS. 





MEAN FOR 



MAXIMUM. 



MINIMUM. 



MEAN. 





MAXIMUM. 







MINIMUM. 





maxi'm 





THE DAY. 











JULY. 



Reduced 

 to 



Freezing. 



Reduced 

 to 



Freezing. 



Time. 



Reduced 

 to 



Freezing. 



Time. 



Dry 

 Bulb. 



Wet 

 Bulb. 



Dry 

 Bulb. 



Time. 



Wet 

 Bulb. 



Time. 



Dry 

 Bulb. 



Time. 



Wet 

 Bulb. 



Time. 



In Sun. 



Sunday, 17-- 

 Monday, 18-- 

 Tuesday, 19-- 

 Wedntsday, 20 . 

 Thursday, 21. _ 

 Friday, 2?.. 

 Saturday, 23.. 



29.579 

 29.523 

 29.611 

 29.686 

 29-553 

 29.596 

 29.646 



29.618 

 29.596 

 29.690 

 29.742 

 29.638 

 29.638 

 29.722 



a. m. 



a. m. 

 12 p. in. 



9 a. m. 

 12 p. m. 



a. m. 

 12 p. m. 



29.508 

 29.446 



29-542 

 29.632 

 29.500 

 29.546 

 29.586 



5 P- m. 

 4 p. m. 

 a. m. 



12 p. m 



2 p. m. 



6 p. m. 



3 a. m. 



73-6 

 69.3 

 74 7 

 77-3 

 78.3 

 73-3 

 72.0 



66.6 

 61.3 

 65.0 

 68.0 

 69-3 

 66.0 

 65.7 



81 

 74 

 84 

 83 

 87 

 77 

 79 



2 p. m. 



4 P- m. 



3 P- m, 



5 p. m. 

 3 P- m. 

 3 P- m- 

 3 P- m - 



72 

 63 

 68 



I* 

 72 



69 



68 



2 p. m. 

 4 P- m. 



4 P- m. 



5 P m. 



2 p. m. 



6 p. m. 



3 p. m. 



64 



62 

 66 

 69 

 69 

 66 

 65 



12 p. m. 



6 a. in. 



6 a. m. 



6 a. m. 

 12 p. m. 



5 a. m. 



5 a. m. 



60 



59 

 60 



65 

 64 

 62 

 61 



12 p. m. 



6 a. m. 



6 a. m. 



6 a. m. 

 12 p. m. 



6 a. m. 



5 a. m. 



131. 

 126. 

 130. 

 123. 



135. 

 127. 

 139. 



Mean for the week 29.599 inches. 



Maximum for the week at 9 am., July 20th 29.742 " 



Minimum " at 4 pm., " 18th 29 446 " 



Range 296 " 



Dry. Wet. 



Mean for the w;ek 74.0 degrees 65.9 degrees. 



Maximum for the week, at 3 pm. 21st 87. k * at 2 pm 21st, 72. " 

 Minimum " " Sam. 18th 62. " at 6 am 18th, 59. " 

 Range " " 25. " 13. " 



WIND. 



HYGROMETER. 



CLOUDS. 



RAIN AND 



SNOW. 



U 



Z 

 



c 



I 



10 



JULY. 



DIRECTION. 



VELOCITY 

 IN MILES. 



Distance 

 for the 

 Day. 



FORCE IN 

 LBS. PER 

 SQR. FEET. 



FORCE OF VAPOR. 



RELATIVE 

 HUMIDITY. 



CLEAR, 

 OVFRCAST, 





 10 



DEPTH 



OF RAIN AND SNOW 

 IN INCHES. 



7 a. m. 



2 p. m. 



9 p. m. 



X 



n 



Time. 



B 

 (j 



E 

 6. 



« 



E 

 & 



o> 



E 

 rt 



E 

 d 



B 

 0. 



s 



In 



S 

 p. 



n 



B 

 & 

 0* 



Time 



of 

 Begin- 

 '"g- 



Time 



of 

 End- 

 ing. 



Dura- 

 tion, 

 h. m. 



Amount 

 of water 



Sunday, 17 



w. n.w. 



w. n.w. 



n. n.w. 



217 



6 



4.40pm 



•537 



.663 



■495 



71 



63 



7° 



3 tir.cu 



2 cir. cu. 















4 



Monday, 18. 



n. w. 



w. n.w. 



w. n.w. 



238 



9% 



11.40 am 



•433 



.429 



•449 



73 



51 



61 



1 cir. 



7 cir.cu. 















2 



Tuesd >y, 19. 



w. n.w. 



n. w. 



w . 



219 



6H 



1.50 pm 



•457 



.460 



• 554 



69 



42 



64 







1 cir. cu. 















X 



Wednesday, 20. 



w. 



w. s. w 



s. w. 



156 



*K 



1.30 pm 



■537 



•534 



.612 



71 



49 



62 



4 cir.cu 



3cir.cu s 



10 











1 



Thursday, 31. 



w. s. w. 



n. w. 



n. n. w. 



227 



A 3 A 



3.20 pm 



.614 



.609 



.568 



68 



S' 



67 



3 cir.cu 



4 cir. cu. 















8 



Friday, 22. 



n. w. 



n . n.w. 



n. n. e. 



82 





8.50 pm 



•495 



.564 



.568 



7° 



61 



67 



2 cir. 



9 cu. 















8 



Saturday, 23. 



n. 



n. e. 



n. n. w. 



140 



2 



2.30 pm 



.489 



•564 



•595 



74 



61 



76 



8 cir.cu 



4 cir. cu. 



1 cir. s. 













Distance traveled during the week 1279 miles. 



Maximum force 9% lbs. 



Total amount of water for the week. 

 Duration of rain , 



DANIEL DRAPER, Ph. D. 

 Director Meteorological Observatory of the Department of Public 



o hours o 



Parks, New 



. o inch, 

 minutes. 



York. 



