1881.] 



MICROSCOPICAL JOURNAL. 



35 



Surely every teacher of science will 

 find this work of great assistance, 

 more especially in the physical 

 sciences it is true, but in other bran- 

 ches it will also be of great value. 

 The number before us contains, be- 

 sides other articles, a description of 

 the Normal-Barometer and Mano- 

 meter of the Imperial Commission of 

 Berlin, and there follows a very inter- 

 esting contribution from Dr. Forster 

 on the " Illumination of the Micro- 

 metric apparatus in Telescopes and 

 Microscopes," and a practical article 

 on the " Production and Investiga- 

 tion of Micrometer-screws," by C. 

 Reichel. We must end this notice by 

 a mere reference to two articles re- 

 lating to the Spectroscope, and one 

 upon " Graphic Methods in Physiol- 

 ogy " both of which are well illus- 

 trated. To indicate the wide scope 

 of the publication we mention in 

 addition the following articles soon 

 to be published : " The Determina- 

 tion of the Constants of Optical Sys- 

 tems," by Prof. E. Abbe ; " Appara- 

 tus for Plant Physiology," by Prof. 

 F. Cohn ; " Grinding of Optical 

 Glass ; " "A New Microscope," by 

 Dr. Hartnack. The parts are issued 

 monthly, and the subscription price 

 is $4.50 per year. 



o 



Ye Microscope of Ye Olden 

 Time. — This is the title of a very in- 

 teresting lecture delivered by Prof. 

 Edward F. Moody before the Camden, 

 N. J., Microscopical Society, and 

 printed in pamphlet form. 



As the pamphlet can probably be 

 obtained from Mr. De la Cour, the 

 Secretary of the Society, we will only 

 refer to it in a few words. 



As a frontispiece there is an engra- 

 ving of an old "double microscope" 

 devised by John Marshall for showing 

 the circulation of the blood, copied 

 from an illustration in the Lexicon 

 Technicum published in 1704. The 

 account of observations made with 

 this instrument as given by Prof. 

 Moody is very interesting, and the 

 entire lecture is well-worthy of care- 



ful reading, although there are a 

 few misstatements which microscop- 

 ists will readily detect. We hope the 

 edition is a large one, so that all our 

 readers who debire copies will be able 

 to obtain them ; for when we have the 

 great energy and enthusiasm of the mi- 

 croscopists oi a century ago thus called 

 to our minds, it should stmiulate us 

 to greater application. It is true that 

 then the entire domain of nature was 

 unstudied, and a new discovery re- 

 warded every effort ; but it is not so 

 much the great number of observa- 

 tions that interests us, as it is the ex- 

 cellence of the results attained with 

 the imperfect instruments at com- 

 mand. Lewenhoek certainly made 

 very accurate observations with his 

 primitive instruments, and the fame 

 of Ehrenberg, who, although he lived 

 not very long ago, still used very 

 imperfect instruments, rests upon 

 results which can only be verified 

 with the costly apparatus of the 

 present time at the expense of long 

 and patient work. 



o 



Moist Chamber. — Prof. Strass- 

 burger's moist chamber is described 

 in the Journal de Photographie et de 

 Mtcroscopie, as follows : It consists of 

 an ordinary slide upon which is placed 

 a ring of paste-board, moistened with 

 water. The object which is to be 

 observed and kept alive is placed in 

 a drop of water on a cover-glass and 

 inverted over the paste-board cham- 

 ber ; the cover is made to adhere to 

 the cell by pressure. The evaporation 

 of the drop of water is greatly re- 

 tarded, if not entirely prevented, so 

 that in this simple manner Prof. 

 Strassburger has kept Spirogyra in 

 copulation alive for several days. By 

 moistening the paste-board from time 

 to time the cover will remain attached 

 indefinitely. 



The drop of water can readily be 

 covered with a small and thin glass 

 before inverting it over the cell, just 

 as in the slide described on p. 24, bv 

 Mr. J. Deby. 



