H 



THE POPULAR SCIENCE MONTHLY, 



Academy, another letter from Mr. Croft was 

 read, in which he stated that he had found 

 a native of the island who could read them, 

 and who was going to teach him the lan- 

 guage, so that he will shortly be able to 

 translate them. Mr. Croft thinks that he has 

 discovered the relics of a great Malayan 

 empire, which extended its power over that 

 part of the ocean at some former period of 

 the island's history. 



Deposits in Steam-Boilers. — Prof. S. 

 Dana Hayes, writing in the American 

 Chemist about deposits in boiler-flues, says 

 that they are of two kinds, both of which 

 are capable of corroding the iron rapidly, 

 especially when the boilers are heated and 

 in operation. The most common one con- 

 sists of soot (nearly pure carbon) saturated 

 with pyrolig-neous acid, and contains a large 

 proportion of iron if the deposit is an old 

 one, or very little iron if the deposit has 

 been recently formed. The other has a 

 basis of soot and very fine coal-ashes (sili- 

 cate of alumina) filled with sulphur acids, 

 and containing more or less iron, the quan- 

 tity depending on the age of the deposit. 

 The pyroligneous deposits are always caused 

 by want of judgment in kindling and man- 

 aging the fires. The boilers being cold, the 

 fires are generally stat-ted with wood ; pyro- 

 ligneous acid then distills over into the 

 tubes, and, collecting with the soot abeady 

 there, forms the nucleus for the deposit, 

 which soon becomes permanent and more 

 dangerous every time wood is used in the 

 fireplace afterward. The sulphur-acid de- 

 posits derive their sulphur from the coal 

 used ; but the base, holding the acids, is at 

 first occasioned by cleaning or shaking the 

 grates, soon after adding fresh charges of 

 coal. Fine ashes are thus driven into the 

 flues at the opportune moment for them to 

 become absorbents for the sulphur com- 

 pounds distilling from the coal, and the 

 corrosion of the iron follows rapidly after 

 the formation of these deposits. 



Conditions affecting the Sex of Off- 

 spring. — In the American Naturalist for 

 January, Dr. John Stockton-Hough has an 

 elaborate article on " The Relationship be- 

 tween Development and the Sexual Condi- 

 tion in Plants." His conclusions are : 1. That 



in plants, and animals as well, that are 

 actively occupied in vegetative, physiologi- 

 cal, pathological, or other efforts which are 

 antagonistic or complementary to the office 

 of reproduction, the proportion of females 

 born during such times is greater than 

 where the plant or animal has reached full 

 developmental maturity and growth, is in 

 good health, and is occupied principally in 

 the process of reproduction. In the latter 

 condition offspring of a higher develop- 

 mental condition are produced, and the pro- 

 portion of males is increased. 2. Females 

 are in better condition, more troubled by 

 disease, or other process antagonistic to 

 reproduction, where they conceive with fe- 

 males than with males ; and they are poorer, 

 because more exhausted and less healthy, 

 by the production of female offspring, than 

 by male products. 8. It is just possible 

 that the ovules from which females are de- 

 rived may have a higher initial vitality, 

 though they be less highly developed than 

 those from which males are derived, yet no 

 egg can properly be said to be predestined 

 to be male or female. 4. That female 

 plants, like female animals, are less highly 

 developed than males, and are the result of 

 an inferior developmental reproductive ef- 

 fort on the part of the female parents. 



Axial Bads in tlie Juglans Nigra.— In 



most plants there is a single bud in the 

 axil of the leaf known as the " axillary 

 bud." In the hickories, walnuts, and some 

 others, there are two or more, one above 

 another, known as supra-axillary buds. 

 When remarking on the sexual characters 

 of the buds of Juglans nigra^ before the 

 Academy of Natural Sciences of Philadel- 

 phia, the specimens I used in illustration 

 made this clear. The abstract in The Popu- 

 LAK Science Monthly for April states that 

 the several-sized buds are on the same tree. 

 It should be at the same node or axis. Of 

 the three buds, one above another^ the upper 

 or largest produces a strong branch; the 

 second in order and in size, a female flower ; 

 and the lowest, smallest, and least organ- 

 ized, the male catkin. The illustration is 

 very pretty. No one should be satisfied to 

 read about it, but examine the walnut-trees 

 and see for himself. 



Thomas Meehan, Philadelphia. 



