Decembkk 27, 1895.] 



SCIENCE. 



893 



At a meeting of the electors to the Wayn- 

 flete professorship of mineralogy, held at Mag- 

 dalen College on Decemiber 13th, Mr. Henry A. 

 Miers, M.A., Trinity College, was elected pro- 

 fessor in the place of Prof. Story-Maskelyne, 

 resigned. The emoluments of the professor- 

 ship are £500 per annum, of which £400 is from 

 Magdalen College and £100 from the Univer- 

 sity chest. 



DISCUSSION AND COBBESPOA'DENCE. 



AN EASY METHOD OP MAKING LINE DRAWINGS. 



It is often difficult to get satisfactory cuts of 

 apparatus or of natural objects to illustrate 

 scientific articles. A half-tone, although the 

 easiest to get, is somewhat expensive and liable 

 to be poorly printed, and, on account of its 

 vagueness of outline, is in many cases not as 

 good for scientific purposes as a half diagram- 

 matic line drawing. To get a cheap cut that 

 can be printed on a newspaper press the origi- 

 nal photograph must be redrawn in lines and 

 dots. But not everyone has the time and skill 

 to make an accurate line drawing, while if the 

 photograph is sent off to a professional drafts- 

 man the expense is about the same as for a half- 

 tone, and the drawing frequently fails to bring 

 out the very point to be illustrated. 



A line drawing with the accuracy of a photo- 

 graph can, however, be easily made in this 

 way: photograph the object, take from the 

 negative a pale blueprint, on the blueprint 

 trace the outlines with as much detail as desired 

 using a crowquill pen and waterproof ink, put 

 the print in water containing a few drops of 

 ammonia, when tiie bluei^rint will fade away 

 leaving the black lines on white ground, wash 

 and dry, make such alternation or additions as 

 are required, and the drawing is ready for re- 

 production by the zinc etching or other process. 

 ■Of course if the photograph is several times 

 larger than the cut is to be, the reproduction 

 will be neater. E. E. Slosson. 



Univeesity of Wyoming. 



[We are glad to give space to the above, 

 although the method has already been recom- 

 mended. For an apparently new and in many . 

 cases better metbod cf. Prof. Hallock's note on 

 page 761 of the present volume of Science. 

 J. McK. C] 



THE MEASUREMENT OF COI^ORS. 



Editor of Science — Sir: Mr. J. W. Lovi- 

 bond, of Salisbviry, mentions in Nature that his 

 system of Tintometer glasses is in constant use 

 in many laboratories and manufactories for en- 

 abling one to record and to reproduce exactly 

 at a future time any given color ; and that the 

 method is so simple that it can be carried out 

 by any intelligent workman. Does anyone 

 know whether these glasses are in use in this 

 country, or whether they can be obtained here ? 



C. L. F. 



SCIENTIFIC LITEEATUBE. 

 ON THE structure OF PROTOPLASM.* 



What is the structure of the most marvelous 

 known substance, protoplasm, ' the physical 

 basis of life,' is a question that has long waited 

 its final answer. Probably the best solution 

 thus far given is that found by Prof. Biitschli 

 in the work imperfectly represented in what fol- 

 lows: 



That the watery, jelly-like material we find 

 in the most actively living parts of all plants 

 and animals has any discoverable structure is by 

 no means self-evident, and it is only by slow, 

 uncertain steps that the conception of a visible 

 physical structure in this soft living matter has 

 become generally accepted. 



The idea that protoplasm is a structureless, 

 homogeneous fluid early met opposition from 

 many who observed here and there facts that 

 pointed to the existence of apparently solid 

 portions in the protoplasm of various cells. 



Eemak in 1837 found the axis cylinder of ver- 

 tebrate nerve fibers made up of very minute 

 fibrils. Frommann in 1867 supposed a fibrillar 

 structure was common to all protoplasm. Stri- 

 ated structures were seen in ciliated cells and 

 in gland cells, while Pfluger in 1869 found 

 fibrillations in liver cells. 



The fibrils were then seen to be connected in 

 the form of a reticulum. Thus Kiipfier in 1870 

 describes the living protoplasm of the follicle 



*XJntersuchungen iiber mikroskopisohe Sohaiime 

 Tind das Protoplasm. Von O. Biitschli. Leipzig. 

 1892. 229 pp., 6 pi. 



Investigations on Microscopic Foams and on Pro- 

 toplasm. O.Biitschli. Loudon. Adam and Charles 

 Black. 1894. 



